A5) Vacuum gauge is fairly new, so I would possibly think it is. It's intermitent, at idle sometimes it's quiet, usually at cold start, when warm it does make more noise at cruise. If you can hear inside the car while cruising, your mufflers are too quiet,lol.
A10) yes, it will stall. Ok good then.By the preponderance of evidence, I have come to believe that your T-port sync is pretty close. And if that is true, then whatever your idle-timing may be, then it too is close. And if that is true then I would be verifying the engine vacuum with a second borrowed gauge. But at this point,knowing the exact idle vacuum is of lessor importance than the compression test results.
As for curb idle in neutral is 950, in gear, warmed up, brakes applied is 650. Will double check to confirm on my next reply.
One more time; Is the 950 curb idle on the warm engine? going to 650 when dropped into gear?What I am getting at, is to be sure the fast-idle cam is fully retracted to off position. Therefore the 300rpm difference is solely to the the TC dragging it down. And then the next question would have to be; Why is the curb idle so high to start with; is it because if the hot curb idle was at a more normal 750 or a bit less with this cam, that the engine would stall when put into gear? And if the answer to that was yes; then we have a problem.
Something is going on that is not right. A 300 rpm drop into gear is excessive. IMO, either the engine is way down on idle torque,or the TC is not working right. And that is why I asked if you knew the stall, by actually testing it.
If the engine is down on idle power, it will be down on power quite a bit farther up the rpm band, and that could be the reason for your screwed up AFRs. The metering rods have to stay down to about 12 or even 10 inches of vacuum. If the compression is not even or very low, then you will be driving into that 12 inches or less zone all the time. And the M-pistons will be popping up, and then the carb will go rich,maybe too-rich,depending on what combination of rods and jets are in it.
I would actually suggest plumbing the vacuum gauge to manifold vacuum and bringing it into the cabin for a few days. Keep an eye on it to gauge your driving habits, and learn how the popping is related to the gas pedal and engine loading.
But I am most eager to see the compression results. Problems like yours always need a good foundation to work from, and proving the engines health is priority one.
The two basic tests for that are the compression test and careful observance of the vacuum gauge.Popping in the exhaust, if valve related, will show up on the vacuum gauge. If it is an exhaust leak problem, the gauge will never see it. If you were to plumb the gauge into the suspect header pipe, the vacuum gauge would read it instantly.
In any case, I at least, will hang around to see the compression results.
Hey, I just thought of something; where is your PCV plumbed into? Are you on the carb port? or on the intake vacuum-tree?
And just to be sure;the vacuum advance can is plumbed into the spark-port right; the port with zero vacuum at idle?
