DuPuis Family Cobra Build

Ted

The pilot formerly known as Twin Engine Ted
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As I've mentioned in other threads, we wanted to build a car. And when I say we, I mean the family. The kids want to help (yeah, it'll 2-3x the total build time, but that's fine). Laurie's all for it, hopefully she'll participate in wrench turning as well. I expect she will.

The goal is a street car, something that we all enjoy building and driving/riding in. I'm not going for ludicrous power, but my goal is somewhere around 375 HP. In a 2400 lb car, that puts around 6 lbs/hp. Not quite to sportbike range, but not too far off, either. And maybe inline with a smaller sportbike.

This won't be a show car. We still want it to look nice, but it'll be something that I won't get heartbroken about getting scratched. The kids will help. It will be a slower build. But it's about having fun, and when we look back on it being able to say "This is something we built."

The Cobra replica is a Factory Five Mk4 Roadster. I purchased the "base" kit. Factory Five offers the "base" kit or the "complete" kit. Neither are really complete, but the complete kit costs an extra $7k for what I didn't feel was $7k worth of additions. The goal is to do this for a reasonable price.

The car is supposed to arrive sometime in the 2nd half of September, so right now is preparing and scouring CraigsList etc. for appropriate parts.

The first score was this Rustang (my spelling is correct):

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It doesn't look like much, but the engine looks like it should power the Cobra nicely, or at least have the potential to do so. Basically, the engine was built for a racer of some sort. The guy who built it wrecked the car, sold the engine to the kid who put it in the Mustang. The kid obviously had no idea how to hook any of it up - the ignition system is all wrong and the carb stuff also doesn't look right. They never got it running. So then the kid's uncle bought it, thought he'd get it running. He didn't have any better of an idea.

Here are the components I could positively identify from a cursory look:

- Edelbrock Performer aluminum heads (not sure whether the larger or smaller valves and ports)
- Edelbrock Performer 600 cfm carb
- Weiand X-CELerator aluminum intake
- Crane Cams roller rockers (not sure on ratio, probably 1.6 or 1.7)
- Some sort of deep rear oil sump
- ACCEL new distributor of some sort with big Moroso spark plug wires
- Came with a new set of Ford Racing 3.73 gears in a box, however there's surface rust on some parts of them so I probably won't use the gears

The ignition is wired all wrong, the carb looks like they got it wrong, too. Someone tried to jack up the car by the oil pan. The rockers are adjusted completely incorrectly. I have no idea if it's got a flat tappet or a roller cam in it, and no idea if it's a 302, 331, or 347. No idea on compression ratio and if it has I-beam or H-beam rods. So it's a bit of a mystery. But, checking some dyno sheets, it looks like this setup has the potential for 375+ HP.

Obviously I'm going to pull the engine. I have to decide whether I want to try to get it running in the car or just pull it and not mess around with any of that.
 
Sounds like a fun project, Ted, I’ll be following along.
 
TLDR especially since you have another thread! Gheesh!

reported
 
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TLDR especially since you have another thread! Gheesh!

reported

My other thread was specific to asking questions about painting the frame. This is the start of the "build" thread.

Personal attack - reported. ;)
 
Cool! Should be fun to decipher whacha got in the deal.

I wouldn’t even try to mess with the carb. To save $ initially, buy a Holley 4776 or 4777 (double pumper). Fuel mileage will suck, but it’ll get you moving without dropping initial dollars on an injection system. The smaller the carb, the more low end torque. Should work fine right out of the box, just set idle and mixture screws (easy).

If the rockers are maladjusted but never ran, should be ok (just look for valve to piston contact, wiped cam, or broken/bent valve train...all good, run it).

Wish I was there...
 
Cool! Should be fun to decipher whacha got in the deal.

I wouldn’t even try to mess with the carb. To save $ initially, buy a Holley 4776 or 4777 (double pumper). Fuel mileage will suck, but it’ll get you moving without dropping initial dollars on an injection system. The smaller the carb, the more low end torque. Should work fine right out of the box, just set idle and mixture screws (easy).

If the rockers are maladjusted but never ran, should be ok (just look for valve to piston contact, wiped cam, or broken/bent valve train...all good, run it).

Wish I was there...

You're welcome to fly on up. :)

I had heard good things about the Edelbrock carb. It was new out of the box, so it should be good to at least get it running, no? Why the preference for those Holleys? I'm not going to do EFI of any sort on it.

I figure one thing I need to do is pull the intake manifold and dissect what I've got for lifters and figure out if the cam is flat tappet or roller. No idea what make it is, but given the other items on the car, I'm going to bet it's a performance cam of some sort.
 
Wow Ted, you don't mess around. Seems like you were just "thinking" about it just last week. BTW - I was the first one who suggested the Cobra. Just sayin. ;)
 
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Wow Ted, you don't mess around. Seems like you were just "thinking" about it just last week. BTW - I was the first one who suggested the Cobra. Just sayin. ;)

That's pretty much how I roll. Think about something, then dive right in and start doing it. Usually it works out pretty well and I have few regrets. Since you suggested the Cobra first I'll give you a ride in it when it's done. ;)

In this case, I really don't need the engine yet. But this was one of those situations where it looked like a deal that was worth buying. Plus the reality is, now is a good time to be working on engine stuff before the kit arrives. Ideally have my drivetrain all set up to just drop in when I get to that point in the process.
 
Boy, you go from "thinking about" to doing in seconds flat! And you get to use your new trailer.

The engine sounds like a good buy, obviously you're going to tear it down for a look. If they built it and couldn't get the ignition right, then proper use of a torque wrench no doubt plumb escaped them.
Nothing wrong with an Edelbrock! Metering rods change a whole lot easier from the top than jets do in the bowl. As the saying goes, a Holley'll win at the track, but an Edelbrock will get you there. You could always tell the Holley boys, they were the one's with the burned hoods from leaky fuel bowl gaskets.
That said, 4130 with vac. secondaries would run good and save you some fuel.

Sounds like a fun build.
 
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Well, that Weiand intake is a single (open) plenum intake, so it’ll flow, but not build a bunch of torque down low. Given your intended purpose, it should be fine. That 600 CFI carb is the right size for that engine and your power level.

Crane Cam - if you can find the part number, you can look it up. Hopefully for streetability, not more than a 272* or 282* duration cam. Check lift as well as, if it’s a high lift cam and you have 1.7 roller rockers, you may encounter spring bind.

Good idea on tearing down the engine. I’d pull it out since you won’t be able to check oil pump pickup clearance with the pan in car. (Hard to pull the pan with the K-member in the way). Given that someone tried to jack up the car by using the deep sump oil pan, I’d check all clearances there.

Forget the car... I’d rather have the engine on an engine stand to do all the work to ensure it’s done right. I’d hate to have to pull that engine again to correct anything and would rather build it right the first time.
 
I've got nothing buy great things to say about Edelbrock. They're very simple compared to most Holly carbs. Sure, you can tweak a lot of the Holly stuff to squeeze out a few more ponies, but that usually comes with its own headaches (like blown power valves, and float adjustments). The Edelbrock took less than 10 minutes from startup to get idle, choke, etc. dialed in. The 600cfm will be just fine to get you going for now. If you find it's not delivering the best results, then look at a slightly larger 650cfm Edelbrock or a Holly equivalent. 600CFM ought to be enough for any SBF/SBC that isn't built to be an absolute monster.
 
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Boy, you go from "thinking about" to doing in seconds flat! And you get to use your new trailer.

The engine sounds like a good buy, obviously you're going to tear it down for a look. If they built it and couldn't get the ignition right, then proper use of a torque wrench no doubt plumb escaped them.
Nothing wrong with an Edelbrock! Metering rods change a whole lot easier from the top than jets do in the bowl. As the saying goes, a Holley'll win at the track, but an Edelbrock will get you there. You could always tell the Holley boys, they were the one's with the burned hoods from leaky fuel bowl gaskets.
That said, 4130 with vac. secondaries would run good and save you some fuel.

Sounds like a fun build.

It was a different guy who built the engine vs. tried to install it in the car and get it running. But yes, I'm going to pull the pan and have a look-see inside, hopefully figure out what it's got for crank/rods/pistons. My guess is the guy who jacked up the car by the oil pan was the same idiot who couldn't figure out the timing.

Well, that Weiand intake is a single (open) plenum intake, so it’ll flow, but not build a bunch of torque down low. Given your intended purpose, it should be fine. That 600 CFI carb is the right size for that engine and your power level.

Crane Cam - if you can find the part number, you can look it up. Hopefully for streetability, not more than a 272* or 282* duration cam. Check lift as well as, if it’s a high lift cam and you have 1.7 roller rockers, you may encounter spring bind.

Good idea on tearing down the engine. I’d pull it out since you won’t be able to check oil pump pickup clearance with the pan in car. (Hard to pull the pan with the K-member in the way). Given that someone tried to jack up the car by using the deep sump oil pan, I’d check all clearances there.

Forget the car... I’d rather have the engine on an engine stand to do all the work to ensure it’s done right. I’d hate to have to pull that engine again to correct anything and would rather build it right the first time.

On the Crane Cam, I don't know if it's a Crane camshaft or just the roller rockers. I'll have to pull the timing cover and see if I can find any identifying markings on the cam itself. We'll see.

I do tend to agree with you on trying to get the engine going on a stand or otherwise not trying to mess around with it in this car. Just pull it from the Mustang, probably try dumping the car as a roller (or maybe part it out... depends) and be done with it. Seems the logical way to go.
 
You're welcome to fly on up. :)

I had heard good things about the Edelbrock carb. It was new out of the box, so it should be good to at least get it running, no? Why the preference for those Holleys? I'm not going to do EFI of any sort on it.

I figure one thing I need to do is pull the intake manifold and dissect what I've got for lifters and figure out if the cam is flat tappet or roller. No idea what make it is, but given the other items on the car, I'm going to bet it's a performance cam of some sort.

If current carb wasn’t jacked with (bending linkage, drilling on throttle plates, installing different air bleeds) and is truly out of the box, I’d stick with it. If you get any kind of hard starting, drivability issues, etc., the Holley DP just flat out works for a large percentage of applications out there. A lighter car with more responsive engine and drivetrain should be able to make do without the need for vacuum secondaries (they will work fine, but may take some additional tuning). I have experience with the Quadrajets and Thermoquads, as far as vacuum secondaries (“air valves” really). One experience with a Street Demon (vac sec) and I got rid of it for a Mighty Demon (Holley copy). Just a preference thing is all.
 
If current carb wasn’t jacked with (bending linkage, drilling on throttle plates, installing different air bleeds) and is truly out of the box, I’d stick with it. If you get any kind of hard starting, drivability issues, etc., the Holley DP just flat out works for a large percentage of applications out there. A lighter car with more responsive engine and drivetrain should be able to make do without the need for vacuum secondaries (they will work fine, but may take some additional tuning). I have experience with the Quadrajets and Thermoquads, as far as vacuum secondaries (“air valves” really). One experience with a Street Demon (vac sec) and I got rid of it for a Mighty Demon (Holley copy). Just a preference thing is all.

One of the reasons why I decided to go with a carb was to learn more about playing with them. I've only owned one carbureted car, my 1969 Cadillac Fleetwood Series 75 (makes @SCCutler 's Eldorado look tiny by comparison), and I didn't own that for long. My tractors and various lawn equipment has had carbs, but I haven't messed with them much. So I know the terms, but haven't done any of the tuning.

My guess is the carb hasn't been messed with too much, given how this kid thought jacking up the car by the oil pan was a good idea and wired up the distributor without an ignition module... he probably din't know enough to mess with the carb. Or if he did, he completely screwed it up.
 
While you've got the pan off, a little plastiguage on the bearing journals could lead to a lot of peace of mind. I mean, you're going to check main and rod torque anyway, RIGHT? Make engine love you long time.
 
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While you've got the pan off, a little plastiguage on the bearing journals could lead to a lot of peace of mind. I mean, you're going to check main and rod torque anyway, RIGHT? Make engine love you long time.

Agreed, I had the same thought.

The story is the bottom end was rebuilt, but I bought it assuming that it wasn't. Someone obviously did something that involved pulling the oil pan off, but how much, who knows.
 
BTW, a GM 4 prong module is an excellent way to go, and dirt cheap. Multiple spark like MSD box. make an aluminum heat sink, and mount it in the breeze and it'll last forever, unlike a Ford TFI.
 
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Nice, no price, care to share for the morbidly nosy? Also, I grew up with carbs, they suck, figuratively and literally, I will not buy another carb vehicle unless I absolutely have to, I hope it runs well for you.
 
1969 Cadillac Fleetwood Series 75
Back in the 70s there was one of those around here that was reputed to run a quarter mile in 12 seconds. Not the limo, I guess, just a run of the mill Fleetwood, but still... The guy who built it owned a speed shop in town, and made custom performance parts for Caddies. The car looked completely normal -- from the side. From the back pretty all you saw was slicks, tucked discreetly behind the skirts.

I'm sure you're going to have a lot of fun with your Cobra, both during and after the build.
 
Here are the components I could positively identify from a cursory look:

- Edelbrock Performer aluminum heads (not sure whether the larger or smaller valves and ports)
- Edelbrock Performer 600 cfm carb
- Weiand X-CELerator aluminum intake
- Crane Cams roller rockers (not sure on ratio, probably 1.6 or 1.7)
- Some sort of deep rear oil sump
- ACCEL new distributor of some sort with big Moroso spark plug wires
- Came with a new set of Ford Racing 3.73 gears in a box, however there's surface rust on some parts of them so I probably won't use the gears

You might have scored a good one on that engine, or bought someone's nightmare.... and aluminum heads are repairable.

Whenever I bought a used engine I expected it to be junk and was usually not disappointed. However I usually at least scored something good out of all the used engines I bought.

Carburetors are so easy. I can't understand why people think they are inferior. Back in the day I could get more power and better gas mileage out of a carb compared to early EFI.

Surface rust is not a problem on the rear gears. Just sand it off and go, being sure to wash everything thoroughly.
 
Ted,

I’m looking forward to pictures and progress reports. Sounds like a great family project that will always be something special for each one of you.

I will certainly appreciate following along as I heal.
 
Nice, no price, care to share for the morbidly nosy? Also, I grew up with carbs, they suck, figuratively and literally, I will not buy another carb vehicle unless I absolutely have to, I hope it runs well for you.

I paid $1800 for the car. Asking price was $2k. Frankly I'm surprised that it wasn't snatched up by someone else. The body is just fine as a donor for a drag race car. The top end components I saw wouldn't make anything that would be record setting by any means, but it's still got some solid parts. I would've even been fine if these things were a step smaller just to get a good base engine in the Cobra in the 325ish HP range to get going. As it is, so far this looks like it has 375+ HP potential pretty easily, whether a 302 or a 331/347 stroker.

We'll see how having a carb does for me. Really, I want a bone simple setup under the hood. My goal is something that you open up and say "Wow, that's nice/simple/clean." I might actually put some effort into trying to make things shiny under the hood, which I don't normally do.

You might have scored a good one on that engine, or bought someone's nightmare.... and aluminum heads are repairable.

Whenever I bought a used engine I expected it to be junk and was usually not disappointed. However I usually at least scored something good out of all the used engines I bought.

Carburetors are so easy. I can't understand why people think they are inferior. Back in the day I could get more power and better gas mileage out of a carb compared to early EFI.

Surface rust is not a problem on the rear gears. Just sand it off and go, being sure to wash everything thoroughly.

Good to know on the gears, thanks. I'll start off by just putting some oil on them so they hopefully don't get any worse.

I've really not had bad luck with carbs either. Well, there was something with the carb on the Cadillac and it didn't like to start after sitting, I think it was a Holley and must've had a leaky float bowl or something. @jesse 's boat (formerly mine) had a Quadrajet on it and despite all the cries of "Worst carb ever!" it always worked just fine for me. Pump it twice, crack the throttle, and it started right up pretty much every time. Don't know if Jesse's having that good of luck on it.

I'm thinking that I'll pull the engine tomorrow and then I can put it on a stand and start looking at it. For one that means I can shove the thing out of sight because damn, it's an eyesore. But then I can start digging into the engine to see what exactly I've got my hands on.

Ted isn’t known to do things by halves. I recall a span of two years between his first flight and his CFI, for example.

15 months from my first flying lesson I bought the Aztec, and flew it something around 200 hours the first year I owned it.

I'm planning on pulling the engine tomorrow. It really classes up the place being out front, don't y'all think?

2018-08-03.jpg
 
The thing about carbs is that a lot of the driveability problems they get blamed for, really aren't the carbs fault. Fr'instance, bad heat risers cause poor fuel atomization when the fuel charge hits the floor of the intake. I predict with that open plenum manifold and a relatively small displacement motor like a 302, your low range is going to be soft, maybe have a hesitation or cold stumble that will be difficult to tune out. But your top range, depending on the cam, will be very strong. A DP manifold will give you a smoother bottom range, but at a cost of top end flow. That's why FI came about, to do away with the compromises. But then playing with cam lift and duration becomes problematic. But here I am telling this to an engineer...
Carbs can provide very accurate fuel delivery for a specific set of circumstances. In my track days we would install Holley main jets for the density altitude at start time. And the atomization in a Weber is to a Holley what a sprinkler is to a garden hose. But they don't handle a broad range of conditions as well as FI.
 
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The thing about carbs is that a lot of the driveability problems they get blamed for, really aren't the carbs fault. Fr'instance, bad heat risers cause poor fuel atomization when the fuel charge hits the floor of the intake. I predict with that open plenum manifold and a relatively small displacement motor like a 302, your low range is going to be soft, maybe have a hesitation or cold stumble that will be dhaifficult to tune out. But your top range, depending on the cam, will be very strong. A DP manifold will give you a smoother bottom range, but at a cost of top end flow. That's why FI came about, to do away with the compromises. But then playing with cam lift and duration becomes problematic. But here I am telling this to an engineer...
Carbs can provide very accurate fuel delivery for a specific set of circumstances. In my track days we would install Holley main jets for the density altitude at start time. And the atomization in a Weber is to a Holley what a sprinkler is to a garden hose. But they don't handle a broad range of conditions as well as FI.

Carb ice is also a big problem, drove me nuts with my 73 charger with a 318, until I figured out the exhaust passage through the intake manifold with clogged with carbon. Pulled the manifold, hacked out the carbon, and never had a problem again. I was never so happy as I was when I got my first electronically controlled fuel injected car.
 
Had a busy day, got the engine out of the car:

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The first observation was that there was coolant in the oil. But very green. They said it was a never run engine but that wasn’t true. It was run, but seemed to have been barely run. Front four cylinders were very clean, enough that I could read the part number off the piston. It has Speed Pro hypereutectic pistons bored 40 over.

I’m not seeing any cross hatching in the cylinders and I’m not sure if it’s a stock stroke or not, but I think it is a stock 302.

Two pushrods were bent. Crane Cams 1.7:1 roller rockers. Heads have 2.02/1.60 valves.

Lifters look brand new, no wear pattern. I made the mistake of pulling one side worth without marking which hole they came out of, but they likely could be used anyway.

So the real question is why the bent pushrods and the coolant in the oil. The head gaskets were brand new, no signs of being blown. The intake gaskets were new too but it did look like they had been leaking and several of the bolts holding the intake down were pretty corroded.

Coolant was green, but who knows what it looked like at some point in the past.

So I see a few potential scenarios (not necessarily mutually exclusive):

1) Overheated/warped head
2) Improperly assembled intake, leaked coolant
3) Coolant got into cylinders causing a hydrolock
4) Cracked intake/heads/block

I haven’t pulled the oil pan to look inside yet, that’ll be another day. I’m somewhat skeptical about the block being usable again, if nothing else because it’s already bored 40 over and may not be usable. But 302s are easy to come by.

Thoughts?

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Are the valves sealing well? Usually hydrolock bends the connecting rods rather than pushrods, I would expect that piston to valve contact would bend the pushrods. It's very possible that there was more than one assembly error and what you're seeing is the result of multiple errors. The engine may have disassembled and reassembled since being started.
 
Are the valves sealing well? Usually hydrolock bends the connecting rods rather than pushrods, I would expect that piston to valve contact would bend the pushrods. It's very possible that there was more than one assembly error and what you're seeing is the result of multiple errors. The engine may have disassembled and reassembled since being started.

You’re absolutely right on the hydrolock. I wasn’t thinking straight.

I haven’t checked to see if the valves are sealing well - that’s another test and if there is piston to valve contact that would explain the bent pushrods. They did the rockers wrong, that I know for a fact.

What’s the best way to try to figure out if the heads are cracked? Probably take them to a shop...
 
Oh, I also think the wrong head bolts were used. Left vs right side had different bolts in different locations and the torques seemed inconsistent.
 
That one real clean hole is suspicious. My guess; it got fired up, run too long, they had an "Oh ****" moment, and put coolant in before letting it cool down. Maybe it got hot enough to stick a valve and bend the pushrod. Imho no choice now but to disassemble the heads, see if they're flat and have a shop magnaflux them and maybe clean them up. At least hit them with dye pen. For the block, you need to have that tanked and fluxed too, if good hone it, deck it, and maybe line bore it. .040 is about the limit, but you have the pistons. And since it'll out, balance the rotating assy
In for a penny, in for a pound.
 
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That one real clean hole is suspicious. My guess; it got fired up, run too long, they had an "Oh ****" moment, and put coolant in before letting it cool down. Maybe it got hot enough to stick a valve and bend the pushrod. Imho no choice now but to disassemble the heads, see if they're flat and have a shop magnaflux them and maybe clean them up. At least hit them with dye pen. For the block, you need to have that tanked and fluxed too, if good hone it, deck it, and maybe line bore it. .040 is about the limit, but you have the pistons. And since it'll out, balance the rotating assy
In for a penny, in for a pound.

That's possible. The one odd thing with all of this is the oil didn't look very new, it was fairly dark when it came out. There is residue in the exhaust, but not a ton. It wouldn't surprise me if the heads got warped somehow. The block doesn't look recently built. Old paint on it. But, it's not stock inside, at least the pistons aren't stock and neither is the oil pan.

I figure I'll see if the valves hold before disassembly. The picture shows one clean piston, but it's a bad picture. Also before I took the photo I also put oil in the cylinders to try to keep the walls in better shape. Reality is the forward 4 pistons are pretty clean, aft 4 aren't. But all of them do look like they had some water exposure, which would support the theory of the warped head. Actually, I should take a closer look at both sides and both heads and post some pictures.

It's all going to come apart, though. Have to see if the heads are cracked or warped. Probably should also check that on the intake.

Some of the valve springs had slight surface rust on them - the valve covers were 100% clean, so however much it ran, it wasn't for long. Not much oil up there. Not enough rust on the springs to concern me really. I sprayed them all down with oil to prevent anything from getting worse.

What's in the bottom end? Who knows and who knows what it looks like. But yes, the block will have to be checked to see if it's cracked. I suspect it's not, though, given the evidence suggesting the coolant was getting breached somewhere around the location of the heads.

I think I forgot to mention that the cam is flat tappet, which isn't ideal but works.

I suspect I'll be able to use the heads, they just might need some work. Also expect the intake and carb will work fine, and the rockers. Hopefully the block is fine. If not, might need another block, but those are easy (and cheap) to come by if need be. The oil pan will need to get banged out from where some idiot tried to jack up the car by it, but that looks reusable at this point. I bet I'll also be able to reuse the cam.

Let's say I'd bought the Edelbrock Performer power pack (heads/intake/cam), that would've been about $2500. Figure $300 for the Explorer engine, another $400 for the carb, sell some stuff off the Explorer engine, some machine shop work, come in around $3000-3500 for the engine probably at the end of the day. So I've got a lot of room with this package to still come out ahead, and I'll be selling parts off of the Mustang (and at some point the entire car itself).
 
Oh, so something interesting - if you look at the rockers, note they have a Ford part number and Ford logo, but also say Crane Cams on them. Turns out they're OEM for a 93-95 Cobra.
 
You’re absolutely right on the hydrolock. I wasn’t thinking straight.

I haven’t checked to see if the valves are sealing well - that’s another test and if there is piston to valve contact that would explain the bent pushrods. They did the rockers wrong, that I know for a fact.

What’s the best way to try to figure out if the heads are cracked? Probably take them to a shop...

A full service automotive machine shop should be able to pressure test your cylinder heads. If they're ok, and the bottom end of the block is OK, they can pressure test it as well.

I would start by putting some solvent into the ports to see if it leaks through.
 
Full disassembly. Inspect them yourself. As you’re doing. Anything that looks ok, take to machine shop to test block, heads, crank, rods, pistons, rings for cracks, clearance, etc.

Cam & lifters- unless they’re new and weren’t run, and it’s the grind you want/need, sell and buy what you want.

Coolant leak- not sure about the Ford block, but sometimes some head bolts/studs may need sealant, so that could be the cause.

Coolant mixed with oil will look like chocolate milk shake or coffee with creamer (if it’s sat a while may have separated out). If it ran with the coolant leak, bearings may show it.

Bent pushrod - best case is it was a geometry issue and the side of the pushrod touched the head (they can’t take a side load). Watch for coil spring stacking solid (cam lift, rocker ratio, shimming/wrong retainer, etc.). If you don’t see piston head contact, shop will tell you if valves are straight.

That’s all I got for now.
 
If the block is bored .040 over and you don’t see any cross hatched honing, the block is done. It likely wasn’t honed correctly. No point in taking a chance on not getting the rings to seal, and I don’t believe there’s enough material left to do another bore and hone to the block.
 
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