Forget going 'new' with any mechanical gyro. If I were you this is what I would do: OH-exchange the wonky AI, buy an RC Allen 2600-3 electronic AI with inclinometer option
http://www.aircraftspruce.com/catalog/inpages/rca2600-3.php, place it in the primary AI hole and use the cannon plug of the electric TC in order to power it (doing so also places it in the main battery bus, which is where you want this puppy in case the alternator craps the bed), then place your OH vacuum AI in the current spot of your electric TC; this may require extending the hoses going to your vacuum AI to reach the TC spot. Discard TC. It's also a modular installation, in that you can just remove the RC 2600 easily and place the TC back when you sell the airplane, and install your digital AI into your next aircraft purchase with great ease.
Alternatively you can do an even easier plug and play installation by placing the RC2600 in the TC location, and placing the OH vacuum AI in its original hole, no hose refitting required in this case of course. I don't like this setup in that I want the more accurate instrument in my primary hub-and-spoke position. Either way, you will gain safety and redundancy in IMC, stay 'legal' and also gain much better attitude information than the mechanical AI can provide in its best day. That is the setup I intend on installing immediately upon finding my replacement aircraft. It's a much cheaper option than going the Aspen route, which I think is ideal, but far too expensive for my budget. I could afford a dynon PFD setup for the same amount as the RCA 2600 + mechanical OH setup, but alas the FAA prices me out of a safer option. Govt for ya....
I googled RCA 22-7 and this is the first YT link I found..
http://www.youtube.com/watch?v=9bfuXe6TIoA
I did that stuff solo and it was funny to get the leans and my heart rate up in IMC when I was childless and my net worth was that of a broke college student (no renters insurance either, talk about running with scissors) and I didn't know any better. But that's not exactly what I want to be doing in IMC in 2013 with family on board, on a recreational XC flight no less. You gain nothing going that route. Needle-ball-airspeed and decyphering/filtering false information in flight is like landing a taildragger. It's harder, more squirrely, nobody cares you can do it, there's no prize for doing it right, and when you screw it up (which is a high probability for those who fly less than 50% of their yearly hours in IMC) you come out the clag 50 deg nose down 140 deg bank staring at trees.
Everybody is an internet partial panel tough guy. The reality is most crap their shorts when this happens in real life and are years removed from recurrent training in N-B-A. There's no reason they have to deal with this in 2013. But you do have to pay in order to get to a modern level of safety, at least in the certified racket. Vacuum-mechanical gyros in IMC?....
