Hi guys new to the forum and trying to get some insight on an block. I have a 400 block, casting number 4006530. date appears to be 8/10/76. I want to build it to go into a rat rod that's going to get driven quite a bit, not wanting insane horsepower out of it but would like 400-450. My question is, is this block capable and worth building to that? I know the earlier 400s are the more sought after ones but want to know if this one is worth it.

 

I'm not sure it's the earlyer blocks but there is a difference in the lower end casting. I was thinking the later block was better but 400 to 450 hp would be no problem.

Can't you use a iron 383 crank in a 400 block?

 

Should not have any issues getting to that...

 

https://www.440source.com/blockinfo.htm