Please help!!! I have an 1986 monte carlo ss with a 350 that I added a while back (still with low miles) I've went through a lot of transmitions so I let the car sit for almost 2 years. I decided to get the car back on the road and started ordering parts which included new Hughes 700 r4 street/strip trans, 2500 stall, 670 Holley S. A. , headers (full length), exhaust 2.5 inch, and ignition. The cars starts/idles fine but there is very little power from idle-5500, heavy hesitation until 2500/3000, and sometimes carb backfire! I don't know much about engine tuning so please help me move in the right direction. Thanks

 

Usually if it backfires through the carb it's a timing or ignition issue. Make sure you distributor is installed correctly first and foremost. Depending on which ignition system you have there could be many variables causing a backfire.

 

did you figure out the problem.

I am having the same problem. carb is backfiring. The dist is in right, plugs, wires, cap, and rotor are new. Im running a accel super coil. The rest is in the sig.

 

Check to make sure all the valves are opening correctly. You will get a backfire if the intake valve/s stick.

Other than that just make sure its in time and the ignition is good.

 

Bringing this post back to life....

Maybe someone can tell me what I broke...after racing my neighbor with a Ranger and a 302, I found I was running rough, like missing on one cylinder....and now occasionally in low gear, I'll get backfiring through the carb, I have little power in accelleration, and my car sounds terrible...could I have broken a spring or do you think I bent the intake valve or something? Help before I tear the whole thing down....it's my only vechicle and my daily driver!! Please help!!!!

If I didn't give enough info, please ask, don't hate on me!

(Q-jet carb, don't know the metering pin sizes, but the car ran like a dream up until a couple of days ago. Inline filter is clean)

 

Try a compression test first see which cylinder or cylinders are giving you a problem. Then start looking at the valves and valve lifts for the problem cylinders.