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I am having a small problem. When I accelerate and change gears the engine causes a popping sound through the mufflers, almost like a small backfire. Also as I decelerate the popping continues. The problem seems to lessen as the engine heats up.

The muffler people said this was normal with glass packs although I have never experienced it before with the exception of an older 348 chevy rod.

I am running a 185 degree thermostat and an automatic choke that appears to disengage once the engine warms up.

It appears the timing meets Ford's specs for the crate 302 engine of 10-12 degrees..

Could it be I have to rich/lean of a set-up? I am now running duel Elebrock cards 1150 CFM total but they were supposetly jetted for this engine by the original owner who had the same engine in California and when I had the local shop look at it they felt the carbs were jetted properly.


The second carb is does not come on line until 3500 rpms.

It starts fine either hot or cold, although if you by accidient hit the gas peddle before restarting it when warm it floods. It idles at 1000 rpms.,and when given gas runs normal with great acceleration.


Any ideas. I was told the headgasket might be bad, however the engine people did not see any visual indication of this. Should I re-torque the head bolds?
 

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Im hardpressed to think its ur head gasket at this point..is ur car overheating? My first thought is the timing..ur exhaust valves are opening during part of the combustion cycle. Do u have an adj fuel reg? May want to play a bit with that also. When was ur last tune up? If ur stuck on the head gasket thing, which I hope ur not, may want to do a compression test on ur cylinders....usually a good test to detect any kind of leaking.
 

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Reponse to Heating Question!

No problem with over heating. Have two fans and they maintain 190-205 degrees no matter what the outside temperature.

Did have a problem like this a couple years ago now that I think about it. Replaced the Ford racing valve covers with a set of smaller Cobra covers and they were interferring with the rocker arms. might be having this problem again.

Guess the best thing to do is reinstall the Ford covers and while off check the rocket arms to be sure everything is ok.

Might also check the head bolt torque on a couple of the bolts to be sure they are spec'd properly.

Im hardpressed to think its ur head gasket at this point..is ur car overheating? My first thought is the timing..ur exhaust valves are opening during part of the combustion cycle. Do u have an adj fuel reg? May want to play a bit with that also. When was ur last tune up? If ur stuck on the head gasket thing, which I hope ur not, may want to do a compression test on ur cylinders....usually a good test to detect any kind of leaking.
 

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What car is it, the Cobra in your avatar? Glasspacks do crackle and pop, sometimes pretty hard and it could sound like a backfire. Is there any crossover pipe in the exhaust, or is it just straight from the header to the muffler? If there's no crossover, it'll snap crackle and pop like mad.

YouTube - new exhaust dual bullets duals out the rear
 
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