Got my new 350 in the rod finally (it's a 1973 350 rebuilt stock). It's running really good, but for some reason am getting a shot of fire coming out of the exhaust. This only happens when it's at idle in park or neutral and I hit the throttle hard. I did notice it happen the other night on the freeway I got her up to about 90mph and when I let off a small flame came out. Is this due to incorrect timing, maybe carb running rich or someone mentioned re-adjusting the valves after the motor was broke in??? What do you think?
Valves set, carb floats to high, vacuum leak, sticky valve, timing, carb linkage adjustment to accelerator pump, any or all, ................
Are you using stock manifolds ,headers or WHAT? Fire is not going to run thru 10 ft of exhaust pipe..give some detail
Most likely a misfire in the ignition or too lean mixture allowing a slug of unburned gas out the exhaust, when the engine fires so does the exhaust.
If you have glass packs on the car. It's your mufflers. If the exhaust gets real hot they'll come apart like that.
Fire coming out of the exhaust, you consider this a problem? 'Long as the engine is running fine, and you have fire coming out of the exhaust pipe only, I see no problem.
The lakes headers on my A-boner would have a 6" blue flame at cruise coming right out the center, looked cool at night, would shoot small flames out when putting the clutch in after a high speed blast, and also when down shifting to slow the car down. I always thought it was pretty rad.
Kelsey, I was drag racing a friend 33 years ago at twilight in my '70 GTX. (He had a '66 Chevelle). I was several lengths ahead of him and when I backed off at the end of the run, he said flame was coming out both pipes. I consider that a good thing. I wouldn't worry about it. Enjoy your ride! (Love your pinstriping and other artwork, BTW)
Ha, ha, my friend had a Vette with an L88 hood and sidepipes. The BBC was running nitrous. One night, during a race. a sheet of flame blew out from the back of the hood, over the top and flames shot out from the sidepipes. It was quite a sight.
I'm calling it normal, I've had it happen (from what people behind me said) letting off the gas with headers, short mufflers and a steep set of rear end gears. Bob
It's not entirely abnormal, especially with a short exhaust, to get some flame or popping when you let off the gas. You can dick around to adjust it to make it stop if you want, sometimes it's as simple as an exhaust leak and a rich mixture.
What cam are you running. A long duration cam can cause this but really nothing to worry about if that is what it is,, I wish I could get mine to do it. I have flame throwers on my 50 pickup but there is a time and a place and it's not on the highway...lol
Thanks for all the replies. I'm using a worn out Quadrajet I'm almost positive has vacuum leaks, so I picked up a new Edelbrock 600cfm I'll put on there. Also my exhaust comes straight up out of the hood (if it had a hood) like the old derby trucks and they are about 2 1/2 feet tall... basically tight fit headers flipped upside down with glasspacks connected to them. It didn't do this with the other motor but it did have vacuum leaks from that same quadrajet. Anyway, thanks for the replies and I'll see if this new carb helps.
most likely internal leakage from the q-jet. High vacuum under decceleration is drawing extra fuel into the cylinders and out the "stacks", imho.
uhhh........ Glasspacks sticking up where the hood should be? This I gotta see...... I demand pictures!!
Not a rat! A traditional rod... something your young hotrodder would have built back in the day... and could afford... and could drive the crap out of. It does have some personal touches to it, but EVERYTHING on there is functional right down to the custom windshield wipers. It's a '37 Ford frame with a '46 International Cab, custom bed... custom everything else. Grill inspired by the '34 Ford. All new suspension and brakes, power windows and a tailgate that's not welded shut. All old school parts besides the new suspension and brakes. I built it 100% with my own hands and learned a LOT along the way. The exhaust was actually an idea from my father-in-law who is a true blue traditional guy... I know it surprised me too. Next project is a 1929 Desoto... possibly with a Dodge 270 HEMI! I'll get some full shots up soon, if any one wants to see it.
The old motor didn't flame and the new motor does. I was just trying to make sure nothing was going to blow up on me... I just dropped around a grand on the motor which is a lot of money to me. The headers are good ceramic coated headers too, even though you can't see them.
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