Engine not running right

[Dazman63]

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?

 

[Tiha]

Is it a mechanical secondary carb or vacuum secondary?

Either way it sounds like when your secondaries start to open it is not adding fuel. Like a bad power valve, or plug fuel circuit.

 

[Whipsaw]

Swap out the carb and see if that fixes it!

 

[Dazman63]

Sounds like a good idea since I have the carb!

 

[Dazman63]

Update

I took out the Holley 750 the previous owner installed and replaced it with an Edelbrock 650 AVS 2 and that fixed my issue.

Thanks for all the response guys.