So my engine was back firing and me and my dad adjusted all my valves both sides. Runs better, But it still back fires. What could be the problem? Its a Chevy 350 with a brand new mild cam. 600cc carburetor. And new shorty exhaust headers. However I don't have exhaust pipes on my headers just yet because I gotta get pipes to mesh properly with my exhaust. Could it be air coming back up from the pipes causing it to back fire a bit? Like I said we just adjusted all the valves.
Valves may be adjusted too tight. Run all the valves again but only add 1/3 to 1/2 turn after zero lash or when you can't rotate the pushrod with your fingertips.
Could be back pressure from the short pipes, could also be bad valve timing, you might have to tweak your cam
Absolutely. You could also be burning your exhaust valves running it with no exhaust pipes. Open exhaust is fine for a 1/4 mile run, but then you need to refit your exhaust.
Remove and look at the spark plugs. They should be TAN color. IF WHITE then you are running too lean or one of the vacuum hoses is sucking air because it is hard and cracked on the end. These are rubber hoses, so no cracks. If vacuum hoses are good then richen up the mixture for the engine. You will lose the backfiring. I am assuming that the distributor is set right so that the timing marks happen at the right place on the front pulley, of course.
Cam timing off, ignition arcing, ignition timing, intake leak. You don't indicate if it is backfiring out the exhaust, intake or both
