HI there...this isn't about my camaro but it is a carb question. i have a 84 dodge ram that i installed a edelbrock 600 on recently. i also put a set of headers on it. everytime i get off the gas in it it pops quite loudly through the exhaust. the truck has air injection cylinder heads(damn chrysler) and a smog pump. it never did this before so i'm wondering if there is a way to work with the carb to keep it from popping. the truck has 134000 on it and the cam is kinda worn so it runs shi**y anyway. but it's kinda annoying to have it sound like a gun going off when i let off. now the timing is set properly to specs so thats one less variable. it's gotta be to do with the carb. any help would be appreciated since i'm trying to learn how to tune a carb properly.

 

Are you using manifold or timed vacuum for the vacuum advance?

 

Exhaust leaks will sometimes cause that.

 

I'm using a timed vacuum port for advance...i thought of that so i gotta go look at what it should be...it does have a small header leak but it did this before installing the headers

 

Alright well i finally got the time to look at my truck. It's an electronically controlled distributor but it has vacuum advance. i hooked up the timing light and it's slightly retarted from where it's supposed to be. not sure how much till i clean the gunk off the indicator. i revved it quickly and noticed the timing jumps very quickly and returns very quickly. could this along with the retarted timing(supposed to be 10Btdc) cause popping when i snap the throttle shut?

 

sounds like you had better figure out your timing.

carbs need a distributor with a mechanical advance along with a vacuum advance for gas mileage.
you may only have the vacuum advance since you said the distributor is computer controlled which means there is no mechanical setup in the distributor.
this would give crap performance and could cause your popping since the vacuum goes away so does the timing=pop.
Just a thought??

 

Sounds more to me like a back pressure issue, ill bet the truck has some straight pipes or glass packs or something too. IMO it doesnt sound like its a timing or a carb issue, more like exhaust leaks, lack of back pressure...

 

well i did install long tube headers and dual flowmaster 40 series mufflers...only reason i removed stock exhaust was cuz the main tube had collapsed and the manifolds were so restrictive the engine couldn't breath with the new 600cfm carb. so it was spitting through the carb at full throttle. i think it's a timing issue cuz it is retarted to probably 0 when it's supposed to be 10btdc. i'm just gonna buy a mechanical distributor and mess with it that way. should cure it i hope...i'm getting a 408 sb for it soon anyways so idc

 

do you have a balance tube or X or H pipe, or is it just a Y pipe into your muffler?

 

right now it's true duals into 2 mufflers. it pops through both sides.

 

no balance tube or X pipe or anything?
If not ill bet thats what it is...

 

I had the same thing happen with the 600cfm edeljunk that was on my car. But once it was properly set up it never did that any more.

It turned out to be the idle mixture needles too rich that caused the popping. Which sounds about right since dumping excess fuel into the engine and exhaust would be an issue.