I have heard of 500ci out of stockers, I am not big on Chevy motors. I did Oldsmobiles for almost 15 years and we could not get much bigger then 500ci without sacrificing the integrity of the block to much! I would rather go aftermarket when it comes to building something that big, but like I said my BB Chevy knowledge is limited to street builds. The problem with the big cube Oldsmobiles was that the block would stress to much, crank would flex and you would end up with trash if the motor was not built spot on! Even then allot of engine failure has happen when pushing the limits. What do I know I never built a BB Chevy like your talking, that's pretty darn impressive to say the lest!
217/228 .565 lift, XS headers, 3" exhaust, th400 swap FTI 3600 stall. 11.75@117