MY 66 W/302ci IS BACK FIRING STARTING FIRES ON THE CARB HELP !!!

[epmustanggt]

Ok here is the deal, i was driving my 66 mustang with a carb 5.0 in it and when i got on the gas, white smoke came out. so i was thinking a blown head gasket. so i replace the head gaskets and put everything back together correctly. so when i go to start my engine it kept on backfiring and not being able to idle at all. so i found TDC again and tried again. I also tried 180 degrees out and still no luck. it back fired and started a small fire on my carb, but i put it out and everything is ok, so this is where im stuck, i think its still a timing issue but im not sure. i have checked the firing order over and over and tried finding tdc and trying 180 out. so please help me !!

Updated-- OK im 100% sure the timing is correct so now im thinking a blown power valve or maybe valves are ajusted wrong. i just hand tightend the roller rockers to snug.

302ci ho with trickflow highport street heat heads, rpm airgap intake, 650 double pumper, with e-303 ford motorsport roller cam.

 

[12sec67]

what kind of distrib and distrib gear are you running?

 

[epmustanggt]

just a stock 5.0 dist and gear

 

[SoCalCruising]

Youare almost certainly retarded in timing. Advance the timing a bit, get it running, and then put a timing light on it. If you don't have a timing light, advance it, get it running, then loosen retaining nut on dist. and continue to advance dist until you reach max. idle speed. Then retard slightly and go find someone with a timing light. Anyway, this what it all sounds like to me as I've been there several times after pulling the distributor - even when I think I have the timing set (mechanically) correct.

 

[epmustanggt]

hmmm so you guys still think its the timing?? do you think its possible than im one off? do you think it would be backfiring and catching on fire being just one off ??

 

[rbohm]

the three most common things that cause backfiring are;

1: wrong ignition timing, usually too far retarded.

2: timing chain stretch.

3: an intake valve that tends to hang open(usually one that is bent slightly).

the order they are listed in is the common order.

 

[69Rcode_Mach1]

If you just hand tightened your rockers, then I recommend you go through and adjust all the valves properly. Then tackle the timing, it is one or the other usually.