Ok MSD ignition, 15* initial 36* all in by 2800 , total checked with a dial back light. I know MSD says no dial back. My timing mark really doesn't jump, but may be off. I'm not really sure. Anyway..Idle sounds OK, I think it could be better. I just noticed reving at like 2500-3000 I get a slight popping sound from the muffler like ( rrrrrrrrrrr pop rrrr pop rrrrrrrrrrrrrrrr pop pop rrrrrr pop ) NOW my dist is connected to PORTED advance. I then tried MANIFOLD vac and the same thing happened. THEN I disconnected it all together and it went away! What it that telling me? Can anyone explain?

It's telling you that the vacuum advance is adding more advance than your particular combo can handle. I had the same problem when gas went from 93 octane to 91. All of a sudden I'm getting this surging and what felt like a miss at cruise. Cut about 4º from the vacuum advance and all was well again.

It could also mean that your vacuum advance can on the distributor could be ruptured causing a vacuum leak at the distributor. Pull the V/A hose off at the manifold and blow into the hose. If you can blow air into the hose the can is bad.


Bob

I went to a car show last night and drove with the advance disconnected. I now get a slight surge when cruising at around 55. Could it be that my all in (36*) is around 2800-3000 rpm and I'm cruising at around 2400 rpm? I pulled over and connected the advance and the surge went away. Also you cant hear that slight popping sound I mentioned when driving, only when idleing and reving to 2500.

when was the last time a complete tuneup was done. Check everywhere for possible vaccum leaks as well.

when was the last time a complete tuneup was done. Check everywhere for possible vaccum leaks as well.

New motor , new everything. Like I said full advance hooked up and ported it does the same thing. I checked the timing. I'm at 18* initial 36* total. I'm using a black bushing to get the 18* mechanical. With vac advance hooked up I get 50* total. SO..18+18+14vac equals the 50*. With no vac I get no popping. It's very slight , but there.