Got one of these a while ago out of a bargain bin, the numbers say it is from a 74 bus, I got it going in my bug, 1600w/ 34 pict 3. Timed it according to the spec website that everybody uses, type 2 .com or whatever it is, 4 deg atdc at idle. Terrible pinging problem....yuk. then ditched the dizzy, back to 009. Tried again later, wanting the performance a vac diz gives, this time I timed it at 32 total at 3000 rpm, retard plugged... excellent results!! power, throttle response, all good. static and idle TDC. perfect. Well today, (first sunny day in months!) i hooked up the retard, started and idled fine, it is at 10 atdc on idle:) nice steady slow idle, runs good, only problem it pops and cracks on decelleration going down hills etc throttle closed. Supposedly the retard decreases pollution, and I want to do my part short of buying a hybrid, so is there a remedy for the popping backfiring on decelleration, short of opening the throttle a bit?