Technical Timing with Dual Quads - HELP!!!!

If you look up to Post 107, just put the front rod on the bottom as opposed to the top where it is. Otherwise it's basically the same, just dialed in where the front carb tips in a little sooner.

 

If your not able to get a different balancer just get a different timing tab.

 

If I read through everything correctly here is what I would do confirm TDC, next read about ignition timing. Understand ported, manifold, total, initial and vaccum Gm engineers really messed up with picking that camshaft 290/350 8 to 1 compression This motor would work better with rv or stock cam. But you got work with what you got. I have read instructions on setting up that engine with igniton timing plus other gm crate engines. On some of their engines they say dont run vacuum advance, I think thats weird.

With that cam and compression and 91-93 octane gasoline don't be surprised if it likes 42 degrees total. So if it was my engine, I would try this run straight 1 to 1 linkage on carbs. Next for a starting point 37 degrees of total timing to be safe with vacuum advance disconnected and plugged while checking total timing. At this point I would only run vacuum advance if I could adjust it down to 10 degrees. Then I would plug it into a full time manifold source. Then go test.

 

I agree with you that the combination would probably prefer less cam with as low compression as it is. Alternatively it would probably like a bit more compression, too. That said, I'm not unhappy with the combination at all now that it's sorted out. It has plenty of power to move the car along just as good as the 394/Roto10 ever did. It also runs at 180 degree tops, hasn't detonated on 87 octane, has averaged around 20 mpg in mixed driving (better than that on the highway) and has been able to run speeds in OD like a modern car on the highway. Honestly it's been wonderful. Maybe there is some more power to unlock out of the combo, but to be honest, I don't care that much. I have about 4K-5K miles on the combo without any issues, it looks good, sounds good, runs good. I ain't touching anything.

 

If your idling on both which I do on my dual quads you should get a Unisyn and an aluminum carb cover to get equal vacuum on both with idle mixture screws…I’ve been running on mine for 7 years. I’m not familiar with your AVS carbs. View attachment 6047588

 

A little late to the party but wanted to chime in anyway...

I always check the float levels and clean Edelbrocks. Yes even brand new out of the box. And the pressure is super finicky. about 5 1/2 pounds is where they like. More than 6 lbs and I've seen issues.
I always use a regulator and a good quality fuel filter.