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ignition problem?

D

dons

New member
I have a 1973 440 chysler engine.it starts right up idles great, when in neutral if wind it up it goes up well backfires thru carb near top end. when u take it out under a load it runs smooth no misses, while under load and above 2300 rpm the engine just wants to die and again back fires thru carb . I have checked the following. no water in fuel, new fuel filters, new fuel pump. the ignitions are Mallory electronic and new eldelbroc carbs. Thanks
 
Is the ignition system advancing correctly as per the OEM progressive advance curve?

If you are uncertain...... mark off your harmonic balancer and strobe your timing marks as you run through this problematic RMP range.
Plot these numbers out in graph form and compare to your OEM advance curve.

.
 
Are you running low on fuel PRESSURE at high speed? That will do it, and it can drill your pistons. You can find out with a pressure gage installed after the pump. Look for at least 5 pounds pressure.

Jeff
 
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