Pop pop on exhaust side
Something not adding up here......
When I saw the vac gauge reading shows 22" in post #14, I thought the cam must be stock...or close to it; missed 703. Hence my earlier post based on 22"of vac. No way you can get 22" from a 703 cam. Faulty vac gauge?? Others I see using it are getting 14-15" at idle.
So I think Mattax has nailed it: too much T showing above the blades. Veeeery easy to check: if the idle mixture screws have little or no control over idle quality/rpm, there is too much T slot exposed at idle.
Now that I am aware of the cam in use, it will want a LOT more timing at idle for optimum idle quality & tip in response; probably 25-35*, which you can achieve by using man vac adv [ MVA ] to provide the extra timing. Read the threads on MVA on this forum. Getting extra timing at idle will also reduce t slot exposure because it makes the engine more efficient; therefore less fuel is reqd & t/blades can be closed more. So before messing with the carb, idle ign timing should be sorted so that the correct amount of bypass air can be added.
Unfortunately, you have bought one of those overpriced MSD dist that does NOT have an adjustable VA unit....& it will not accept an adj unit. Better off buying a cheap HEI with coil in cap & it comes with adj VA unit. I can buy them here for $100....& have used heaps of them.
See below..
Something not adding up here......
When I saw the vac gauge reading shows 22" in post #14, I thought the cam must be stock...or close to it; missed 703. Hence my earlier post based on 22"of vac. No way you can get 22" from a 703 cam. Faulty vac gauge?? Others I see using it are getting 14-15" at idle.
So I think Mattax has nailed it: too much T showing above the blades. Veeeery easy to check: if the idle mixture screws have little or no control over idle quality/rpm, there is too much T slot exposed at idle.
Now that I am aware of the cam in use, it will want a LOT more timing at idle for optimum idle quality & tip in response; probably 25-35*, which you can achieve by using man vac adv [ MVA ] to provide the extra timing. Read the threads on MVA on this forum. Getting extra timing at idle will also reduce t slot exposure because it makes the engine more efficient; therefore less fuel is reqd & t/blades can be closed more. So before messing with the carb, idle ign timing should be sorted so that the correct amount of bypass air can be added.
Unfortunately, you have bought one of those overpriced MSD dist that does NOT have an adjustable VA unit....& it will not accept an adj unit. Better off buying a cheap HEI with coil in cap & it comes with adj VA unit. I can buy them here for $100....& have used heaps of them.
See below..
