Thanks for confirming that, Dwane. The only thing i could dig up on the net were dimensional drawings which indicate that a 4.25 would work, but i want to make sire before pulling the trigger on the rotating assy. I am actually going to call you for a camshaft/ lifters for this engine. I was thinking about a hyd roller for this but wanted yo talk to you about the durability of the lifters for street. This will be a 95% street car with 10.4 comp , stealth heads (std port opening) , headers, thinking about indy dual plane, i have an hp 950, 727, and 3.23. (I do have 3.91 i could swap to). HEAVY b body. 4165 with me in seat. If vacuum is a problem, i will solve it by ripping power bouster off and swap msnual disc master on car:). Im perfectly happy with manual disc.