Are the cylinder walls on a normal 350 block thick enough to bore and stroke it to displace 400ci?
I've heard that the difference in the 400 blocks is the added cylinder wall thickness for the bigger bores.

For my next engine I want more than 383 ci. what the biggest I can go on a 350 roller block?

 

I think I've seen 391 before.

 

Buy a 400, that's the only way. You're not going to be getting 50 cubes over stock.

 

Can't happen. You'd have to make the bore .125" larger, plus change the crank from 3.48" stroke to 3.75". Most 350 blocks won't go past .060" over, and even at that, if you don't actually hit water somewhere, the walls are paper-thin, so it usually causes cooling problems.

Stick with the 383. The couple of extra cubes you can get by boring farther aren't worth it.

It's possible to put a longer stroke crank in it, but that magnifies the whole rod clearance issue. If you have no experience dealing with such things, or you aren't willing to pay an experienced machine shop lots of expensive labor hours to do it for you, it's not for you.

 

Unless you are Car Craft, then you. They took a brand new 350 block (Mexican variety) and bored it .060 over and stroked it to a 401. Just by a 400 and be done with it. I would personally be worried about boring a block to the limit...

Good luck,