350 stalling and poping out the exhaust

I'am new to this site but I need some help with a 350 vortec, when I give it the gas slow everything fine but if you mass it it will stall and then pop back out the exhaust, and when its cold cranking it will pop or like run backward then crank right up, could it be the ignition switch or power valve in the holley, I have replace the distributor with a MSD HEI,adjusted the valves, timing set at 10 with advance at off, adjusted the carb idle mixter screws to get the highes vacuum,new wires & plugs, check for intake leak cant fine nothing, I am out of ideals, could used some help, thanks

Welcome to the site! Was it OK before you replaced the distributor, or has it been running OK with the MSD HEI and just started doing this?

It has doing this sense I installed the engine, started with a points distributor and change to MSD, when I first installed the engine it would backfire throught the exhaust so bad it blowed the mufflers out so I install a set of flowmasters and adjusted the valves,change the distributor, adjusted the carburtor and set the timing, it still will backfire on start ups and when you press the pedal to the floor it will stall out, could it be the power valve in the holley or the ignition switch, I am lost, any advice will be thankful, later

Timed correctly? :confused:

I'm with JBoss, timing issue.

Keith

It could be just as simple as having a couple of plug wires crossed.

I agree, crossed wires. Check the firing order.

I would check the spark plug wire and make sure you have the correct firring order.
Is the engine new or used? if it is Used you might have a bent valve or over tightened the the rockers. Timming could also be off a bit.
Kurt

timing set at 10 degrees with vacuum off, new plug wires 8.8 mm, firing order right 18436572, it ran better yesterday but when you first start it it will pop back out the carbuator and when it starts it still has a little stall to it like it not getting anought amps to the distributor that why I thinking on the igntion switch, it in a 55 chevy and there no telling how old it is, thats the next thing I going to change, thanks for the help and if you think of anything else please let me know,Thanks Bill

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Originally Posted by dei355

timing set at 10 degrees with vacuum off, new plug wires 8.8 mm, firing order right 18436572, it ran better yesterday but when you first start it it will pop back out the carbuator and when it starts it still has a little stall to it like it not getting anought amps to the distributor that why I thinking on the igntion switch, it in a 55 chevy and there no telling how old it is, thats the next thing I going to change, thanks for the help and if you think of anything else please let me know,Thanks Bill

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Re-adjust the valves.

I change the pump nozzles in the carburetor and its running great, engine builder said it was not geting enought gas when accelerating, runs sweet, thanks for the help and the advice.