My guess is a big block Chevy. Distributor at the back of the engine, sump has its hump in the back, it's pushrod, and the exhaust ports are evenly spaced. I can't tell if the intake ports are siamesed or not since the intake manifold isn't clearly visible in the picture.
As to the EGT, really hot. I'm going to guess around 2000F or higher. When we used to lean to 1750 TIT and turn the lights out it was about that bright, and the lights are on.