I was just making sure that I have this correct. 350 and 400 heads are interchangable correct? If so, then I could use vortec heads on a 400? Would I make more power doing some port work on the vortecs or would I make more power doing port work on the stock 400 heads? I don't want to go too wild since this will be a street engine. So some minor cleaning up and porting work for better flow. Also, I have some GM pink rods that I wanted to use, could I use them in a 400 buildup with a stock 400 crank? Thanks in advance for your help.

 

If you're going to get custom pistons then yes you can use those rods. For the heads just make sure you match up all water passages from the block to the heads including the steam holes.
Don't forget to make the head gasket match as well. Normally 400 gaskets have the steam holes.

 

all SBC heads will bolt up to any SBC block. there are differances in the intake bolt patterns and steam holes for a 400.