I saw 10 psi @ the manifold @ 5K rpm. I was still running the 2-core intercooler @ that time. I went to a very large spearco for the D1. I installed it myself, and, it was alot of work, but, worth it. I was running a comp cam 215/ 222 I/E @ 0.050" with .560 lift/ 110 IN-CL/ 114 lsa on the 383. Also Afr 190 heads with 54 chambers. I had to do alot of tuning in the timing area with LT1edit. I did not like the comp cam. rpm was down, so, I'm installing a cam motion 231/ 240 I/E with 550 lift with same lsa/ IN-CL. This should bring me up to 3K to 6.5K power range, and, I like to rev. I originally has a crane 2050 cam 218/218 I/E with .498 lift and 106/116 In-CL/ lsa. I really liked that cam. It screamed with the p600b @ 9psi.
---1997 SS M6.