I've got a '76 L-48, 4-spd, stock except for the exhaust. The new exhaust is a true dual setup, 2 1/2" with magnaflow mufflers. I love the performance and sound, but under deceleration and compression braking I get those light backfires and pops (sounds like a ratty old Ford with glasspacks) through the pipes. Anything I can do to eliminate those? I've got the timing set at 8 degrees BTDC now, should I play around with it either direction? Any way to richen the idle mixture a bit with a stock emissions Q-jet? I've never checked the compression on this motor, I suppose it could be a burned valve or something and I just didn't notice it with the single exhaust. It runs pretty good otherwise, though.
Dave