I just dropped the stuff off Friday. I am not putting it together. The machine shop I dropped it off to didn't realize the valves were so big in the head, they said they would have to clean the block up and check to see what is available. That is why I got on here to do as much research as I can to see what is available. I have almost nothing in the 396 block,$50. Will I have the same issues with these valves/heads with a 454 or 496? Also can I buy a pre-assembled short block 454 or 496 that will work or will I have to custom build one to work with these heads?