340 popping through carb at low RPM.

Matrick69 said

When I first got it running, it would pop from the exhaust at idle once warmed up. After I got the timing sqaured away, that issue is gone. Once and a while it will pop out the exhaust as it idles down at a stop light. Usually only one or two pops and it quits.

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You said you have the TIMING SQAURED AWAY.
What is the initial timing at idle?
Do you know how much total centrifugal advance the distributor has?
Are you running a vacuum advance?

There is a good possibility that the carb is lean on the primary side.
Have you tried tuning the carb per the Edelbrock tuning guide?