Carb Size for 454?
 

I have been fiddling with the 454 in my K-20.............It runs better, but falls on it face on a hill and still seems sluggish when you stand on it. The previous owner put a new Edelbrock on it, and I haven't checked yet, but I am wondering if he didn't go big enough for this size cube engine. What should I be running on it? Everything else is spot on, and it runs well, other than the problem I mentioned above, it just doesn't seem like its getting the fuel/air on a pull. I put all new filters/plugs/wires on it so it isn't any of that that is the problem, and it has an electric fuel pump that works really well.

Still haven't checked the block #'s, but I am wondering if this isn't a smog engine and it will be a turd?

Re: Carb Size for 454?
 

750 cfm to 800 cfm to 850 cfm depends on the cam size
750 for sure

Re: Carb Size for 454?
 

if its a stock or near stock 454 Id use either a Q-jet or a 750 cfm carb.
Ive got a 770 Holley on my mild 454. John

Re: Carb Size for 454?
 

It looked to me like a 650 or something off a small block, but I'll have to look closer................They got an adapter plate on it to make it fit. May have to go back to a Q-jet :)

Re: Carb Size for 454?
 

I'm using a Jet Stage II 800 cfm quadrajet and my 454 seems to like it alot.

Re: Carb Size for 454?
 

Agree with rage'n, but you could probably get away with a 700 if you're in stock form and not spinning past about 5000 RPM. If you've got enough cam to need 6000 RPM, go with an 800. If 6500, go 850.

Re: Carb Size for 454?
 

:agree: A Q-jet flows about 780 CFM, and even some fairly warm Corvette 454s shipped with them. I'd stick with a vacc secondary carb.

There are a lot of things to look at with the symptoms you're noting, but I'd be surprised if it's the fuel pump. My guess is a) timing advance or b) the point where the secondaries are kicking in or the metering rods.

I'd keep the Edelbrock and tune it vs. making a change. They're great carbs for engines making <= 1.2 HP/CID FWHP.