Solutions for too much compression

Valiant360420 said

My distributor is a Mopar Performance vacuume advance equipped unit with an orange ingnition box.
The advance curve is ...
9 deg at 1500 RPM
17 at 2000 RPM
22 at 3000 rpm
Give or take
The Vacuume advance adds about 16 degrees.

Engine vacuum at idle in neutral is about 18.

Compression test with only 1 plug removed is around 180 psi.

Carb is a 750 Holley vac secondary. Never touched the jets.
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Click to expand...

There’s two parts to tuning a carbureted engine: timing, then the carb itself.
My thoughts-
Timing curve is too fast. If you have “two light”, or “one light and no 2nd” spring in the distributor you need to get a stock distributor “light” spring and either install in the empty spot, or replace one of the “MP light” springs. Or lighten the counterweights. The advance shouldn’t start until about 1500 or so and be all in above 3k.

I would use the vacuum on the ported vacuum port. You can adjust the level of vacuum required to move the plate by inserting an Allen wrench into the vacuum nipple on the vacuum can and engaging the screw inside there (11/32nds ?)

You MUST tune the carb. Check the idle vacuum in gear once you have 15-18* initial. Then buy a power valve that’s about 1-2 inches below that vacuum reading. I would also jet up 2-3 jet sizes (I think it has 72s), and buy the vacuum secondary spring package and install the purple spring.

That’s what I’d do.