Playing around with my new timing light and vacuum gauge. I have a 1972 318 motor, everything is stock except the Edelbrock Performer intake, 1406 Carb, and Pertronix II ignition/flamethrower II coil. It has manual brakes, power steering, no air cond, vacuum advance carb, stock exhaust manifolds.

Was idling high and popping out exhaust. Fixed all of that.

Set:
base timing to 9° @820rpm
total timing to 35° @2500rpm
vacuum advance hooked up, total timing sits around 49° @2500rpm

Idle set and wanders between 800 to 830rpm

Idle screws adjusted till popping stopped and a vacuum of about 21" achieved (around 2.5 turns out from seated)

No vacuum leaks detected....yet


There are a couple of things Im still trying to work out.

1st:
Engine has no more backfire, runs fine and revs up fine but it shakes a little. Not bad, but it's definitely not smooth. Timing light lights up on every spark plug wire, but sure feels like there's a small misfire or maybe plugs fouling. Next step I'll pull them and check.


2nd:
Is it normal for the rpm to get back to idle speed VERY slowly after reving up? When I let off the throttle, it takes the engine about 10 to 20 seconds to fully return to idle speed. The throttle linkage is not stuck it moves freely.