6 pac carb question !!!!!!!!

[dentwizgen]

Hey fellas,
I have a 70 challenger with a 440 6 pack set up. I bought the car as a turn key car this summer and it runs pretty good. The guy told me that the only mods was the biggest cam that mopar makes. Not sure of the lift.
Here is the problem.
When I start the car is seems to run fine about 1000 rpm then after it gets warmed up, it will runs at higher rpm then slower rpm. Bounces all around . If I turn off the car for a little and then restart it, it runs at a lower rpm say, 800 or less then high again. I looked for vacum leaks , tighted all the gas fittings but still can't seem to locate the irregular ideling.
I am not sure if the carbs need rebuilt.
When I got the car, there are 3 feul lines that come from the rear. The main gas line, the return line and also a vent or over flow line. The over flow line was caped off. Could this have something to do with it?

Sometimes , even after that car is warmed up, it will not start right up. I have to pump the gas pedal several times then is slowly starts ?

Any ideas ?????
I had a friend check the timming and he said it was fine.

Should I have the carbs rebuilt. They are original to the motor. Real V code car. Elderbrock

 

[Chryco Psycho]

check the other thread you started

 

[DTCMMLF]

I'd look for a crack somewhere in the Intake manifold! Sounds to me (guessing here) that you have a leak that the heat from the motor is making your fuel mix an issue as the metal expands the additional air is not consistently fed to the engine. Does your exhaust smell rich???? Think the previous owner set the carb on the heavy side to compensate for leakage... Again, just a guess!! Good Luck!!!

The torque settings on the aluminum manifolds is light and someone with a heavy hand, may have tweaked the settings a little on the high side.

 

[moper]

What is the timing set at? What ignition and distributor? Do you own a vacuum gage? They can be bought pretty cheap and you'll need it.

 

[the wall]

one common problem you might have is the mech advance in the dist is starting to advance right at your idle speed and big cams like high initial timing so when it idles up its idling to high to let the timing back if you load it slightly and bring the idle down the advance goes away and runs slow again until the advance start up again. if this is the problem you either need stronger springs in the dist to hold the timing back till a higher rpm or you need weaker springs to just let it advance all the way. i have a 509 cam and it starts with 13 deg and as soon as i starts it goes full advance at idle i also have a 440 6 pack