Engine stalls after driving 1/2 hour

[NickD1967]

Hi everyone,
I have a 71 Challenger 440 727 torq trans. After driving for a half hour the engine will not stay running in gear unless i double pedal at stop. This website has been amazing, let me know how to give back!!! Look forward to my car running strong to bury chevys!!
Regards,
Nick

 

[the wall]

just a few guesses... idle circuit to lean so when the choke is on it runs but when it warms up and choke comes off not enough fuel. idle set too low and when the choke is on the high idle cam idle up enough and when it warms up the cam rotates to the low curb idle and its not set high enough so it stalls. does it have trouble starting after it stall? then maybe the float level is to high and it dripping from the booster nozzles and flooding it. maybe the carb needs a thick gasket under it to keep the heat off it and the fuel is boiling in the carb. the thing to determine is if the idle is set high enough then does it need more fuel or less and then why.it could be the distributor is advancing to fast so when its in gear hold the idle down the centrifugal advance goes away and severely retards the timing and the engine struggles to stay running

 

[74CudaDave]

Will it idle if you pop it into neutral? What kind of carb?

 

[NickD1967]

Will it idle if you pop it into neutral? What kind of carb?

Yes that's what I have to do at light. It has an 850 Holley double pumper.

 

[74CudaDave]

If the 850 is like my 750, double check the secondary idle screw setting - the one you have to take the carb off to adjust. Mine was doing the same thing until I set that and now the idle is good.