Motor idles fine run good under light and medium loads but once a heavy acceleration or two run through it the motor will break up and die after I let go of the gas. I can catch it if I throw the 727 in neutral and give it some gas. I've tried raising and lowering floats on my holley 750 ultra dp and increasing my electric fuel pump to 7psi. The problem persists and need to fix it asap.

 

Sure sounds fuel related to me. How's the pickup look?

 

750 is a pee shooter for that engine.

 

I Agree.... Sounds short on fuel...
Try an 850 or 950... I'm assuming the rest of the system is adequate...

 

Check fuel pressure maybe bad pump.

 

I would suspect the fuel bowls are not big enough to feed your monster, it runs out of fuel

 

I would think that the 10% or higher ethanol has screwed up your carb. It did it to several of my cars that sit for a week or longer.