I have a 8RT that has just been rebuilt in a 1952 Ford F1 and found that the block is cracked at the top of the valley, behind # 1 valve springs level with the valve guides. I didn't discover the crack until I put water in the radiator in preparation to crank it and noticed water in the oil.

I guess I will have to find another block.
Can anyone tell me what blocks will work with my 8RT? A 8BA looks the same but I am not sure. What are the years I can use and what are the differences?

 

Any flat V8 from '48 to '53 will work, but you want to stick with engines that use the wide belts. Car engines after (I believe) '51 used narrow belts. You can use the block from a Car engine, just swap the pulley and water pumps from your old engine.

One caveat; Cars in '48 still used the older style V8, you don't want that. Trucks got the newer 8BA-style engines first (in '48), then in '49 all used the newer style engine.

 

I'm pretty sure your 8RT has some of the lowest compression heads. If you find an 8BA, use it.

Pulleys, water pumps, and fans/generators can generally be swapped to address the belt issue(s).