Fine Tuning a 360 Magnum with a Brawler "Double Pumper"

Another interesting thing that just came up, I’m going to check my fuel bowl level again but when idling for a couple of minutes (delivering pizza leaving the engine running) it starts to idle lower and lower. I left the truck with it idling at 700, now it’s idling down to 400 and vacuum dropped from 20 to 15, but if I give it gas everything is back to normal.

I am also getting slight bucking when around 1500rpm and barely on the throttle (cruising), it’s not horrible but it’s enough to move me back and forth in the seat.