74 2 with 44 webbers. pops and back fires through the carbs. doesnt happen when idling or gettin on it. right side seems to shake though on idle. very noticeable. any ideas?

You have to do your homework here... Start by adjusting the idle mixture screws. If the carbs don't respond check for a plugged idle jet. You should also verify all the standard tune up stuff; timing and valve adjustment.

how often do the valves need adjusting. also i know i have a intake leak. when turning the air mixture screw all the way in on just one barrel theres no change in idle

If it's shaking that usually means one or more cylinders are not firing (or there's no fuel to ignite. Check the plug wire routing correct order on cap and correct cylinder. Either feel for a cold exhaust pipe or pull one plug wire at a time while running to find out the offending cylinder.

Then you can determine if it's spark or fuel related.

If fuel related, I would start w/ cleaning the jets and re-setting the mixture screws. Then a full sync.

Linkage is the #1 cause of sync issues.

Get the vacuum leak fixed as this could be the genesis of all your problems.



A clogged idle jet will cause this. . .

If you can't remember the last time the valves were adjusted, start there ...

Everything else will be a complete waste of your time if the valves are off.
Andy

If the problem is limited to just one side your floats could be set wrong, starting at the basics and working your way up will solve it. Especially if it has been awhile since the last complete tune up.
Has the car ever run right or is this ongoing? How long has it sat?

fixed. i took them off the car and completely took them apart to clean. ive done this twice before. kit once. i noticed one of the pump arm rollers was missing. made a couple of calls and found a shop in phoenix that had one for $20. nice guy. does sand rail and machining. these are 25 year old 44 webers. the guy said pretty good carbs. anyways i cleaned them real good put them back on and it runs like a rocket ship again. fires right up, idles and then goes. no problems. thanks for the replies