[69-CHVL]

Ok, took the car out yesterday, runs great as usual. Noticed a little more lean surging/bucking at cruise than usual. Probably cause its been a little cooler out lately. Looks like I'm going to 76's. Is it possible that the manifold vac advance is pulling too much timing? Would timing impact jetting? I know you guys have hotter engines and are running around 74's, cant see why I have to run so rich (72 is stock in the front).

 

[JOHN WILSON]

Going from 38 to 41 degrees advance will lean out my A/F ratio by ~.2 or so.
(12.6:1 with 38dg to 12.8:1 with 41dg). No other changes, timing only.