Hey people,I have a new H.O 350,300 miles now and it started to backfire on drivers side.It only does this when im giving it the gas to get up to speed limit.It idels great and the pipes are white. You can give it 2500 rpms in park and it runs very smooth.If the temp is under 170 it doesnt do this,but at 195 temp,will start back firing on drivers side only, when u start to give it the gas.I have never hit it hard yet.Hell guys I havent even lit the tires or heard the 4 barrel yet.
Some drive items
350H.O 350,timing is 12,idel is 800
350 TRANS.2200 stall,shift kit
373 possi gear
edelbrock rpm vortec intake
speed demon 650,pipes are white
dynomax headers,1 5/8 , dynomax ultra flows it goes from 3in colectors to 2 1/2 in pipes,to 2 1/4 mufflers,and 2 1/4 on back
I did the break in at 2500 rpms for 20 minutes and also did the 4000 rpm and let off to back down to 2000,6 times in 2nd gear
Any ides what this could be would be great,as I am stumpd,
Thanks again,
Rick

Is your timing set at 12 with vacuum advance blocked off? It has to be. Back fire through carb, or out the back?

Yes Stacey the vac advance is blocked off,and its back firing threw the exhaust,left side only,and only after its above 175 degrees,car has been runing at 195-200 on this new engine,is a 195 thermastate,the one g.m calls for this engine,also is a new 4 core radiator,thanks Stacey,
Rick

Hey people,engine is running fine now,one of the spark plugs ceramic casings was cracked.Man im so happy its fixed,was thinkin the cam or valves were bad.
Any how thanks for the help
Rick