The vacuum is ported and at idle it is non existent. I left it off the distributor and plugged the line to the carbs. I then only get the mechanical advance and whatever the HEI has built into it. It is better but did not eliminate the the popping back in the rear carb. I talked to Tom Langdon and he said to check a few things. I completely disassembled all the jets and checked them. He feels the popping back is lean and could be a plugged jet, but I have not found that in the two times I’ve had it apart. I’ll keep trying different things. I enjoy the challenge. I do have a heated manifold and it gets pretty warm so I don’t think it is related to a hesitation problem. It is quite responsive to the throttle and really doesn’t have a dead spot. I can try some more timing adjustments tomorrow. Maybe I should check out the front carb and see how it is set up? It seems to work fine. I could switch them places and see if it fallows the carb. I’m going to check my compression too, now that I have a few hours run time on it. Could possibly be a leaky valve on my new head? Although it sounds good and runs smooth.
