The greddy turbo is sort of small, but will spool up very quick. My friend has one and we are running the same amount of boost, but I have a Garrett T3 .63 .60 57 trim. He spools faster, but I pull on him on top of third. Yes, a sohc can handle 7psi even more. I have heard some running up to 14 on stock engine with a revmax kit I believe. The one with the 5th and 6th injector. later