I have a 78 Bronco with a 400 engine and aHolly 750 carb, which I plan on replacing with a Edelbrock 650.


Anyways, when I’m in second gear and increasing the RPM to switch into third it’s like the engine starts to die. I can drive okay as long as I don’t accelerate too fast. While at idle if I step on the gas to increase the RPM to over 2000 it acts as if it’s going to die.


I replaced the filter, fuel pump, adjusted the accelerator pump and verified the timing.


Any ideas on where else to troubleshoot?

 

Check the float level in the carb
Check for debris (crap) in the carb bowl that can plug the jets
Have you played with the timing and the vacuum advance signal?
Switch from spark port to manifold and try it
Do your wax valves work? TVS's
There was a delay valve in the timing vacuum line from the factory on yours
Maybe play with that vacuum signal to the vacuum advance
Maybe get an I/M test done (on manual mode) and gat a printout, to check the CO and HC
That will tell you if the power valve leaks and / or functions, and the state of tune with the HC's
Good luck