Misfire at cruise, popping/afterfire at 3000RPM

Mattax said
I either missed or forgot that.
Remind me why is it all in at 2800?

This was a while back, but it was when I was trying to measure the curve. I started at 14 advanced, idle speed was around 850 IIRC, then revved until it stopped advancing, which was at 2800 RPM, and the advance was then at 24. New distributor from Summit. We had talked about changing springs to see if I could get more total advance, but the transmission took the front seat for a bit.

Edit: I was typing this response while you posted. I forgot I had a separate thread where we talked about that.

George Jets said
Guessing that center carb is running Lean, outboard carbs running rich.

Just as a test in the driveway, can you block your outboard carbs on the manifold, and bolt on one of the outboard Carbs in the center?

Will it bolt up for the test or are the bolt patterns different?

The bolt patterns are the same, so I think it would be possible.