Can you explain why an 88 would be good on a 5.3 but too big on a (larger) 5.7? Not being d i c k i s h, genuinely asking.
Doh! I left that one hanging big time.
The 5.3s are running TH400 with trans brake and leaving at 5500-6000 rpms on the 2step and shifting at 8500-8800 rpms and 35-40psi boost.
For a truck with a stock 5.7 it would take forever to get into boost. and when it did make boost you would need some big wastegates to regulate it down to 5psi.
If he would have mentioned a 60mm turbo then that would be perfect for lowish boost (5-8psi) and almost no lag. but then again what injectors and how would you tune a TBI for that?