Holley Carb

[Aussie67]

I am currently running a 600 cfm holley on a close to stock 302.

I know they work ok but what are the collective thoughts of changing down to 500, 2 barrel?

 

[ZFORCE]

Should be fine, I think Ford 4 barrel Mustangs originally came with a 480 cfm carb?

 

[Aussie67]

Thanks mate. I don't think I have ever seen a 480 over here. Are they a common item?

 

[msell66]

First off, why the need to change? Is it a dog with a 600? If really interested to try one, do it on a dyno so you know what the difference ends up being.

 

[Aussie67]

Not really a dog, just seems a little to much carb for a close to stock engine.

 

[Horseplay]

Going from a 600 4 barrel to a 500 2 barrel what are you hoping to see? You'll get better daily driver economy out of the 4 barrel and provided it is jetted and set up right you'll likely see more seat of the pants fun with it too. I fail to see any benefit changing to a slightly lower CFM 2 barrel.

 

[Midlife]

Going from a 600 4 barrel to a 500 2 barrel what are you hoping to see? You'll get better daily driver economy out of the 4 barrel and provided it is jetted and set up right you'll likely see more seat of the pants fun with it too. I fail to see any benefit changing to a slightly lower CFM 2 barrel.

I absolutely agree. The primary 2 barrels of the 4 barrel carb is more fuel efficient than the 2 barrel carb. If you think it is too much, why not go to the 480 cfm version (Autolite 4100) that was used in all A code Mustangs and is an excellent carb. The Summit version that is quite popular is based on the 4100 design.

 

[Aussie67]

OK, so I'll keep the 600 and put a recon kit through it. Its running but dies/ struggles on acceleration. Wanted to check the general thinking before going kit or new.

 

[Horseplay]

What you're describing is likely carb related and a good cleaning alone could fix it but doing a standard rebuild wouldn't hurt either. Be sure to check your incoming fuel line and filter as well. It could simply be a low or inconsistent fuel pressure issue too. If you don't have a fuel pressure gauge in place by the carb, now would be a great time to add one.