<Starts right up, have to feather the gas to maintain a rough idle.
that could be rich or lean mix, vacuum leak, or fast idle cam not involved...I need more specific info. such as "runs out of fuel and pedal squirts accelerator pump spray for engine to catch for a second"
<All emissions were removed and got a weber carb with aftermarket headers and cam.
details on the cam? how far from stock?
did you seal all the emissions ports against vacuum leaks for sure?
<I've done what I know to adjust the carb,
depends on the jet orifaces
<and verified the timing...really rough idle.
book timing specs will make an engine start...depending on your spark advance and such, "on the money" final timing can be different than book spec.
< If it's the gas what can I do to be sure, and how do I fix it?
is it gas?
do a compression check to test the valve seats, those numbers tell a lot, you hope to see 150 psi... 120 and below will show up as rough idle.
get a pocket spark tester you touch to the wires from sears for $10 and verify you have good spark to all cylinders. (and good enough plugs). a night time eyeball check is good to find spark leaks.
spritz the intake for vacuum leaks and check all vacuum hoses for dry rot, and plug threads...vacuum is critical on rusty vintages.
if all the foundation is right, then you check inside the carb for float level. dirt, maybe loose jets... as well as the butterfly pivot for wear.
timing by ear is retard is slow and throaty, advance is fast and thin. the advance has to working, but idle is the meaty middle part, not too retarded.
advance and lean makes heat
retard and rich runs cool and plugs foul.
idle mix should be a mini-tad rich so it doesn't stall at lights, and thick enough to jump as you first open the butterfly.
timing should be advanced enough so the engine sounds young.
but you have to prove compression and vacuum or it's chasing phantoms.
