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Can't rev over 4500 rpm

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19 69 GTX

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Got a new 69 gtx 440 and when on the throttle it hits hard but I hit 4500 rpm it starts popping and cracking won't go past 4500 rpm. Any idea what could cause this. I swapped ignition boxes and put a fbo one on it same issue. Has a new carb as well. Could something in distributor be the issue or maybe coil. It has a stock distributor and msd coil but coil runs through a ballist. I didn't think you would run the msd coil through ballist it needs full 12 volts.
 
Stock points distributor? Can definately be point float at that RPM.
 
Could be a lot of things but if your distributor is pretty old I would pull the cap and see if there is side to side play in the shaft, signaling a worn upper bushing. I think the ballast resister is OK with just an MSD coil.
 
Have you tried disconnecting the tach? alternator? Had 2 of these recently. One we figured out. The other has has extensive testing and still has the issue.
Doug
 
dvw said:
Have you tried disconnecting the tach? alternator? Had 2 of these recently. One we figured out. The other has has extensive testing and still has the issue.
Doug
Click to expand...

The tach could cause this?
 
Hopefully you don't have "valve floating" going on...your symptoms reminded me of this a condition I had in my '67 GTO.
 
My sisters 340 duster sat for 30 years , had to replace the valve springs, ran like a raped ape after that , but I agree with the others to start with the distributor
 
Nevada dan said:
My sisters 340 duster sat for 30 years , had to replace the valve springs, ran like a raped ape after that , but I agree with the others to start with the distributor
Click to expand...

Was going to suggest valve springs...
 
I had similar issues with my engine…went to heavy valve springs….man what a difference it made….
 
Power wire to ECU not on 12v side of ballast resistor?
 
Just throw a Standard UC12 Coil on there , any coil with a positive primary resistance of 1.4-1.5 OHMS and see if anything changes

Easy swap if you have any jobber stores close by
 
The ballast requirement should be dependent on the fbo box . I do not know what they like. (Instructions?)
 
RemCharger said:
The ballast requirement should be dependent on the fbo box . I do not know what they like. (Instructions?)
Click to expand...

I had the stock orange box on it and swapped to the fbo box a friend had and it did the same thing
 
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