Back fire problems

[aa-1159]

I've got a 73 Duster, 383 40 over, mild street cam
750 holley,Power valve is good,Plenty of Vaccum,
Everytime I get on it , it backfires
I just reset timinig for 28 to 36, seems to solve most of the backfires but still has a small one, How much is too much timing, Do I need more timing or should I be looking for other problems
Any help is good help, Thanks, Greg:banghead::banghead::banghead::tongue10::tard::clock:

 

[OwdKasd]

How about any exhaust leaks??

 

[67Dart273]

Explain the timing, you talking about total advance, or what?

What do you mean "Bacfire," is it puking back out the carb?

Under what conditions, high RPM lots of throttle, or initial off idle?

If off idle, could be the accellerator pump is not working, not enough initial timing

If high RPM you could have a bad plug wire, two crossed, or low spark voltage, or even a flat cam, or valve hung open.

We need more details on how you set the timing

Does it idle OK?

Does it "rev" OK with hood up, in neutral? Have you visually checked the accellerator pump shot?

 

[aa-1159]

Lots of questions, I'll try to get all the answers I can
Newly rebuilt Motor
Back fires as soon as I hit the gas
Idles great, New Carb. Timing set at idle
Has a curve in dist. Maybe a better dist. might help

 

[70aarcuda]

check your accelerator pump ....make sure it squirts gas as soon as the throttle is moved...and check the squirter size....might need to go up a size or two..

 

[6.1cuda68]

check your plugs for the deposits on them and make sure you dont have a lean condition