a 400 block, 30 over with 400 pistons 30 over and 5.7 rods and 400 crank is what size?

If they are pistons with the pin boss set up for the 5.7 rods it would be 406. If not I think the pistons would stick up past the top of the deck ;)

hm something i didnt know. so looking in summit how can i tell what the boss is set for?

They should have a notation for what rod length.If not look on the piston manufacturers website or call em.

Here look up these pistons on Summit's site TRW-L2489F30 & TRW-L2467F30 Click on the application and they will tell you the rod length and for which crank stroke.

2467F30 are 30 over flat tops with valve 2 valve recesses I think, but what is up with 5.7 rods?
Shouldn't you have 5.56" for a 406 on a 400 crank?

its funny but the combo i was thinking was just put in julys chevy high performance. explains everything. now i may be thinking work off a 350 since the heads i wanted to use need to be machined for the 400 block and im not to into spending $1300 on heads to have to spend another $200 to get them machined to work with the block. this stuff drives me nuts. they put it up against a 505bbc and all under $6500 except they dont really mention until deep in the article they just had some motown blocks already machined laying around. im not so fortunate

I read the article you're referring to. They used a production 400 block, Scat 3.875" crank and Scat 6" rods, Ross .040 over pistons w/1.063" compression height-->422ci.. You could use 5.7" rods and the std. 3.75" stroke but you need to find a piston with the correct compression height. Std comp height with the 5.56 rod is 1.545". If you want to use 5.7" rods you need to find pistons with a 1.425" compression height.

The only machining you need to do on the heads to make them work in a 400 is the steam holes. You can do this yourself with a hand drill.