Is Edelbrock 500 Cfm Enough Carb.

[Dougsters]

Have a 1966 C-Code C-4 and having it rebuilt next week to stock specs.But having a mild hydraulic (dont know specs yet)cam installed ,I also have performer intake and Edelbrock 500 cfm carb.on car now with Hipo exhaust manifolds.My builder said a 600 cfm would have been a better choice vs what I have.This a senior cruiser for me so should I upside my carb over an opinion or is 500cfm ok?Thanks everyone.

 

[Moosee1955]

You already have the carb. If it was me I'd bolt it up and see how it runs. You could always fatten up the 500 Cfm carb some if it's lean, with larger jets and such. If it turns out to be too small, you can plunk out for the bigger carb. Theirs charts available online to help with carburetor selection. A good friend of mine has a paper version of it. Any speed shop should be able to help, or maybe one of the forum members can post one for you.


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[Dougsters]

Thanks for responding so I have the 500 cfm carb. on car now, before engine rebuild. But did have to lean (using chart)out 4% from stock.For sure if builder says carb is limiting the engine performance,will have to consider a 600 cfm. Did a lot of research last year and thought 500 would be a better fit.

 

[Moosee1955]

When I used calculator, I think it said 640, but who knows. It will depend on how high performance you go. Holley makes various power valves and jets to make your 500 closer to a 550 or so. But it's your dime, if you want a new carb, that's what you do. Me I grew up poor, so when I could improvise, I did.


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[RacerJames]

The stock 4v carb for a K code was only 425 cfm, so a 500 on a C code should be great for a "senior cruiser". if you're racing, you want to squeeze every last hp from your engine regardless of mileage or comfort. When you're cruising, mileage and comfort are factors. It's my (ASE master) opinion (along with several engine performance authors) that most small blocks are over-carbed and if this is a stock 289 with a mild cam, 500 cfm will provide plenty of air and fuel to those small cylinders.

 

[Dougsters]

Thanks for your response RacerJames. I think because the shop that's doing rebuild ,does mostly race engines.They are in the squeeze every HP out of build mind set.But in my case this social security cruiser is a slow and steady ride.lol

 

[65Ccoderagtop]

I believe the stock 2100 Ford 2 barrel had about 250cfm. So a 500cfm should be fine unless you go crazy low with gears.

I just picked up a Holley 7448 350 cfm 2 barrel for a stock 1965 c code. Putting a manual choke back on it as well. Not everyone wants to race a 50+ year old car.

 

[65Ccoderagtop]

Thanks for your response RacerJames. I think because the shop that's doing rebuild ,does mostly race engines.They are in the squeeze every HP out of build mind set.But in my case this social security cruiser is a slow and steady ride.lol

I should add , That I used the Holley remanufactured EBAY store so my 7448 was $229 with a 90 day warranty. 0 to 50 should be responsive and still roll out on the highway nice.

 

[MustangIIMatt]

500cfm is plenty.

The only way it won't feel like enough is if you hold the throttle wide open to 6000 rpm, then it might run out of steam around 5500rpm or so.

I've run 350cfm 2-bbl carbs on engines up to 400 cubic inches before, even on the 400 a carb that small is great off the line and runs out of steam around 4000 rpm, and a 600cfm falls off around 5500.

Everyone tends to go too big on carburetors, but all you're doing is making tuning more difficult and hurting throttle response.

 

[RacerJames]

This thread should be a sticky.
I ran a stock 2100 on my Maverick stock car for 5 years (The rules at the time mandated a stock cast iron manifold with a stock production carb.) We kicked the camaros and novas butts regularly. We ran up to about 5500 on a mild cam 302 with flat top pistons. Man, those were good times!

 

[rbohm]

a 500cfm carb is plenty for a mild 289. remember the K code was a 480cfm carb(not 425).

 

[RacerJames]

That's right, 480 CFM. I mixed up the rules I ran under with the reality. Nobody ever checked our "inferior" 4 barrel specs, the inspectors were much more knowledgeable and concerned with the Holley world. Heck, when the 2 barrel rule was instituted, the rule was it had to be stock production for the engine. So, we went out and got a Variable Venturi from a 351W. Those things flowed 570 CFM, and ate the stock Chevy's with their puny Rochesters for lunch!

 

[flstang65]

I am on the side that says 500 is plenty. I put a 550 on my stock 289 and had to jet it down a little to make it happy.

 

[Dougsters]

Update: So based on engine builder unable to tune Edelbrock carburetor(small shavings in carb.passages) ordered new Quick Fuel 600 cfm carburetor from summit.This was builders recommended carburetor.Not bad for $300 out the door.And made in USA .But if you read my other post regarding post rebuild problems the carburetor is not the big issue as it's not installed yet.Thanks All.

 

[flstang65]

You will be happy with the QF. I have installed several of them on customers cars in the past.

 

[Dougsters]

You will be happy with the QF. I have installed several of them on customers cars in the past.

Thanks for your reply.So had QF 600 installed.Stock primaries jets where 68 mm ,way to rich so builder reduced to 62 mms. Dang it runs much smoother then Edelbrock 500.But my fuel mileage went say down 9 mpg,try to keep off secondaries.How much can I lean jets out .I saw the QF 450 carburetor has 58 mm primaries. And 10 mm smaller on secondary jets also. Any thoughts for stock 289 and mild cam.Thanks All

You will be happy with the QF. I have installed several of them on customers cars in the past.