I have a stock 327 all done with hi comp pistons I got for free. All ready to go but sitting for a while. I plan on pulling out the pistons and rods and replacing them with 6" rods and flat tops. Then mating that with some 76cc heads for 8.5:1 cr. I plan on using megasquirt, a 750DP holley, and twin turbos. How do I size turbos for this setup?

PS: The reason I plan on going with the 327 is because the block is ready to go and I have a forged crank for it. Would a 2 bolt be ok for 600hp+ or should I go with a 350 4 bolt? I have plenty of them laying around as well but would need a clean and bore. I'm trying to keep this as low budget as possible but don't want to screw myself for the future either.

 

2 bolt mains can be splay drilled. Splayed 4 bolts are stronger than the factory 4 bolt mains.

 

i like the idea of 4 bolt if possible or splay the 2 bolt mains as its stronger like said above.

600hp on motor or at the tires?

600 on motor or close to 500whp would be something like 30-32 lbs a min of air flow per turbo. Assuming something like a 5800-6000 rpm peak power, you'll need 9-11 psi to do that power. A good turbo for that would be something like a 56-60mm turbo. Going by Garrett's maps, that would be GT3076R. That would cover 600-900 hp on your 327

 

Looking for at least 500hp at the tires, hopefully 600. Yea a splayed block would be great but is it necessary? Orr, is yours 2, 4, or 4 splayed? Do you think i will have any turbo lag with the 327? I knwo they're not the torqiest (yep made up a word) engines but I figure pretty much any v8 shouldn't really have 'lag', correct? I hate turbo lag...

 

Keep the turbos on the smaller side with a tight .6x a/r turbine, it should light up the turbos pretty quickly. Probably could get away with straight 4 bolt main. My 383 was 500-520whp on spray with 4 bolt main. Ran just fine. My turbo setup is on Dart SHP block with splayed 4 bolt mains. 2 bolt I'm not sure if I'd run 500-600whp on. PRobably can be done but not sure how long it would last. If you already have a good shortblock, try it out and just run 500-600whp on race days and on the street, turn it down abit.