Describe pops? If you stomp on it does the engine spew out black smoke? It could be that your engine is running rich and unburned fuel is igniting in the headers.

Thanks for the tip....*mumbles*....

Andreas

 

Cheryle, what type of mufflers are you running?

 

do you have glasspacks? They give than dumb crackle sound.

 

No black smoke. It revs smoothly, but when you let off the gas... POP, POP, POP. I guess it's hard to describe here...

I'm running dual flowmasters, but it's been so long since I bought them, I don't remember what kind of flowmaster exactly

 

sounds like its back firing, a girl in my shop class old truck (77 Chevy I think) we doing that, turned out the 2 rear barrels (or whatever you call them) on her carburator werent opening

 

might check timing too or carb may be running to rich (I think, or maybe it's too lean). Does it ever desiel out while driving or shutting her off?

 

It's a brand new carb, so it might need a little adjusting. No dieseling when shutting off. I did notice that it smells kinda gassy when it's idling... maybe it's a little too rich?

 

that makes sence if it was too rich. Mine did the same thing after the motor swap where it backfired on deceloration ( I guess you could call it) but it just was timing.

 

9 out of 10 chebbies around here that have modified exhaust sound like that when getting off the gas... very loud and fast pop pop pop pop. one guy i know really digs that sound and downshifts his auto everytime he stops to make it REALLY loud and annoying. i dont know what causes it exactly, but i'm guessing it has something to do with the size of exhaust pipe used. one exception is our 95 tbi burban with split duals and cheap red glasspacks on each pipe, it is LOUD and DEEP but none of that annoying popping, best sounding chevy i've ever heard. i think the shop kept the pipe pretty small though, which i bet helped tremendously. i dont think you have an engine problem causing it, it's just a side effect of your exhaust setup. what size pipe/tips are you running?

 

It's 2.5 from headers to mufflers and then 2.5 all the way back... dual exhaust

 

my brothers 2000 ta is doing that when its cold (borla cat-back), it quits as soon as it worms up, (qick high pich pops compared to deep sounding back fires) since motors run rich when cold, then it would be a safe bet that its running rich, if yours doesn't quit after it does worm up.

 

probably an exhaust leak at the heads or the collectors. if it pops and then kind of sounds like it's going to try to maintain rpm then it's a jetting problem. i'd inspect the collector gaskets for cracks and/or blowouts. tighten them up too. get some stainless collector bolts--you'll pat yourself on the back later. as far as the header gaskets, those aren't very easy to get to as you probably know (putting those back bolts in without a crow's foot sucks). keeping headers tight is a pain in the butt.

does it do it when it is cold, hot, or both? does it do it if you keep it out of the secondaries?

anyway, 8° is a pretty good spot for timing on a 350. i usually start at 4° and work my way up.

 

Cheryle, definately sounds like timing. I trailered my K20 to the muffler shop(15 miles) after installing my headers at home and before we cut out the old exhaust it sounded fine. After we got the headers on though it would backfire really loud out of the passenger side header. I'm not sure if I hit the distributor during the installation or what, but it was my timing. That would definately be the first thing I'd check, and if you smelling gas check the fuel mixture while your mechanic's at it.

P.S. here's the K20 on the trailer, gotta love that straightpiped Cummins with 7,000lbs on the back! What a beautiful sound!

 

im a newbie here but i hope to shed a little light if possible. when i had my duals put on i drove it home and the same thing was happening. apparently the guy switched the plug wires, i just redid them all and she purred like a lion.