Stock 2bl intake or aluminum 4bl intake

What does the popping sound like.. and are you doing that test to check for a leaky throttle shaft? Would be best to test from the exterior side of the shaft if that's the purpose.

Timing(ignition lead) also plays a big role in tuning as well.

 

The popping is little backfires and sometimes shoots flames, i was thinking i have a bad valve. I was also going to pull the spark plugs and check those out.

 

do a timing check first.. then move to a compression check

 

Ok i will do that first