Chargerfan68, at one point I turned the vacuum down to only 9”. The oil pressure did not fall off, but power did, which we knew would happen. After that pull I tweaked it a little bit higher, power came back, and oil pressure moved a little bit on higher RPM. The two were directly correlated. The 572 we were dynoing has a Milodon pan with two external lines, swivel pickup and Milodon pump cover.

We will have to see what it does when going down the track if we lose any oil pressure or not, and adjust from there.

I know personally, on my own car, when Tim installed a vac pump on it a few years ago. My first day out I was making 1/4 mile runs, at WOT, 7700rpm, 8.80 @ 152mph, it was pulling 15”. My oil pressure though, was 90lbs. When turned the vac down to 10” which is our target number. Oil pressure was 95lbs. Now I had ton of oil pressure and since then we turned the oil pressure down a little bit, but didn’t adjust by cranking the vac up.

I’m not an engineer or engine builder to explain it, I just know that the vacuum pump can affect oil pressure if cranked up too high.