Hey Folks, I need to replace the leaking original Motorcraft carburetor in my newly acquired '76 F150. Even though it passed smog, the truck has a rough idle and lacks power. I think I want to go with the Holley 80452 600cfm model, but am debating whether to get a new intake manifold too, such as the Edelbrock 2166. I have to keep the truck smog legal which restricts what parts I can get. My question is what performance gains will I notice with the carb upgrade alone versus a new intake too? The only other mod on the truck so far is a dual in dual out Flowmaster muffler that replaced the stock rusted out one.
Thanks,
David

 

Not an expert on carburetion but the size of a carb is fairly critical for good oerformance. Too big and it won't run for €¥it!!, and is a pretty common mistake. Take care to size it right for crisp throttle action.

 

This model Holley is supposedly very close to stock (600cfm). I know the high flow rate carbs don't work well on stock engines. I really would like to know the benefits of the aftermarket intake (if any) on a stock motor. Thanks

 

I have an Edelbrock Performer dual plane manifold.
They make one with EGR (3766) if you have to retain that for emissions.

The first gain is that you drop about 50 Lbs of cast iron off the top of your engine.
Better heat transfer makes for quicker warmups.
Better runner design without too much volume that will kill low end.

I have a similar carb to the one you mention. (0-80457-s)
It took a bit of tuning and still doesn't get as good mileage as the worn out 4180 it replaced.

The best thing you can do for power and smooth running is, replace the retarded timing set with a roller chain and gears from a later EFI engine.
It makes a BIG difference over stock, and I have had no problem passing emissions.

Good luck with your new rig!