just got done with my cam change and car is popping threw carb and skipping. it idle fine but when u get on it going down the road it backfires and miss and pops. i set timing and adjusted it no help , re adjusted preload form 1/2 to 1/4 no help, changed carb no help. checked wires 18436572. what could it be? im thinking maybe fouled plugs. had that pop before. please help!!!

 

Only thing I can think of is the ignition timing is off. In order for it to backfire back through the carb your spark timimg is way too early. Did you remove the distibuter?. throw a timing light on it and see if it's correct at idle and when you raise the engine speed.

 

I agree. Has to be timing.

 

To my knowledge there are 2 primary causes of backfires in the intake. 1 is timing which is most likely and 2 is a lean mixture. Check for vacuum leaks. Now your saying you had this popping before the cam swap so its the same as it was before correct? Or am i missreading that?

 

I would pull the distributor back out and reinstall it. could be in wrong. I once had this problem, pulled it, put it back in, adjusted timing, fixed it.

 

its set at 20 with timing light. could that be to much at idle?

 

no pop or anything with two lopes worn off old cam. well had a bad skip!

 

Yes 20 degrees is a bit too much. Should be more like 8-12 degrees BTDC for your base timing.

 

i will try that when i get off the evening thanks!

 

I had the same problem but its either the timing or you have a vacuum leak but you say it will idle fine, I would check the timing and fuel mixture.

 

well car wont run with timing set at 10. got new plugs no change. set preload to 1/8 some what better not popping that bad now. i think i may try 1/16 see what it does. what yall think?