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Carb popping
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Posted by: Trick6960

I just recently finished builiding my first engine and installing it in my car and starting it up. On initial start up it ran just fine but then a couple of days later it started popping out the top of the carb. I am running the MSD 6AL ignition box with MSD distributor and MSD 8.5 MM wires. The carb is a Holley 750cfm 03310-s (not a double pumper). The engine is a BB 454 bored +.60 with TRW forged pistons (L2399) speed pro rings gapped to .018. The crank is a scat9000 and the rods are stock, resized and fitted with 3/8 in. ARP wave-loc bolts. The intake is Edelbrock performer RPM and the cam is also the Edelbrock Performer RPM with lifters. It has a B&M 2600 stall and a TH350 tranny(that badly needs rebuilding or trashing). The only thing I can think is that its a fouled a spark plug or somehow the carb is running to lean or rich. If anybody can help me that would be freaking great.

Posted by: skeezix

Is the cam brand new or used? And, did you replace the lifters as well?

Popping thru the carb usually means a bad cam. I'd pull the valve covers and check each rocker arm lift with a dial-gauge while hand-cranking the engine.

Posted by: Trick6960

yeah the cam is brand new and so are the lifters.....everything is basically brand new except for the main caps and the rods and heads.

Posted by: Mr. P

I don't know if I've mentioned this before, but popping through the carb can be an intake valve that is way open, and way out of adjustment. I had one that was so far out it didn't read any compression, and the fuel charge was actually going off in the exhaust headers and not the cylinder, thus the popping.

Just a thought, Mr. P

Posted by: pauly

SOME TIMES THERE CAN BE A SPARK GAP FROM YOUR COIL WIRE CONNECTINT TO A NOTHER WIRE. MAKE SHURE ALL YOUR WIRES ARE CLEAR FROMM OTHER WIRES.

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