Well hold on...that was at 8000 plus when I measured that. And I had 2.125 inch headers with 4 inch collectors.
Sooooooo...I’m ASSuming I can pull the same with 1.875 primaries and 3.5 inch collectors at 7000. Im also ASSuming that the amount of crankcase depression I can pull is based not only on how well the engine is sealed, but that the amount of depression is based on the efficiency of the system and not the size.
So it’s all conjecture and speculation on my part, but I *THINK* I can do it, based on what I was told before I actually tested it in 1999 and that was 2, maybe 3 inches of vacuum was max.
I hope I’m correct, but I think I can do it.