I have this pop in the exhaust at idle and a little shake/miss at constant higher RPMs. I did a compression test today and was wondering if the compression could be causing my symtoms? Engine is a '67 230. #1 150 #2 155 #3 150 #4 125 #5 145 #6 120 I was going to start with valve adjustment on #4 and #6 first.
#4 and 6 plugs might be fouled or bad. Tight lash will cause popping but why just those two? Timing, crossed wires, cracked or carbon in dist cap, carb/intake manifold leaks cause popping too.(vaccum check for a steady needle)
I added a couple of table spoons of oil in #4 and #6. Compression went up to 140 in each. This motor sat for 10 years before I got the car. Maybe some stuck rings?
