I have an 52 F1 with a 302 and C4 with stock rear axle. Engine is balanced, stock compression, Iron heads, mild cam, stock dist., ported to gasket sizes, headers, and 2 bbl. Holly, 24 1/2" tires.
Runs pretty good but I have not put the front clip and bed on it yet so it is easy to get to the engine so I was thinking about going to a 4 bbl. and am asking for suggestions for street use only.
Also, am I going to want to go to a little higher rear axle ratio? Think is around 3.75/95 or so?

 

302/C4 is a great combo in these trucks. You've made some good improvements to help the engine breathe and run smooth. You didn't specify what your cam specs are but assuming nothing radical, an Edelbrock Performer RPM manifold and an Edelbrock 500 or 600 carb would compliment the work done. A similar Holley carb would work, too, it depends on your preference.

I had a 289/C4 in my 50 F1, many years ago, and I had a 9" rear from a 69 F100 with 3.25 gears. It was perfect. When I first built it I had the stock rear and it was always screaming. Swapping the rear moved the rpm's to a manageable level and let it run great both around town and on the highway.

 

The more info you can give us the better . Your usage - cam etc . A 4 barrel was more or less designed for fuel economy , smaller primary = better economy , total cfm at WOT is the same . 600 CFM 2 barrel = 600 cfm 4 barrel should be the same HP . Gear ratio is relevant to tire size , your rpm at cruising speed and expectations are important .

 

In my pickup I have a 351 w with 2bl and had a C6 , rear differential from an Explorer 3.73.1 gearing. 29 inch tall tires. It ran 3100 rpm at 60mph and was a dog passing a transport. I switched over to an AOD and also changed over to a 4bl, Edelbrock performer manifold and 600 cfm Edelbrock carburetor .Truck runs at 1900 rpm at 60mph and the passing capability is unbelievably better, it made it a much better truck to drive, also runs a lot quieter now too..

 

And let us know what heads you are using. If factory what ones what version, and stock compression ratio does not help us much as stock compression ratios in the 302 ranged from 7.8:1 all the way to 10:1. and 10.5:1 in the Boss. If it is one of the low compression smog heads you may be better off with a head swap that may yield more ponies than the addition of the 4BBL and intake and will be more usable HP as just adding the 4BBL will help on the top end but give you no returns on the bottom end. Where as the head swap will help all across the RPM range.

 

I had a stock 302/C4 in my '63 Falcon and it ran with a 500 CFM 4 barrel Edelbrock carb on an Edelbrock intake. It purred and idles really nice but it had get up a go when I mashed the pedal. So I'd say with the goodies you have listed, a 600 would be idle. Just my two cents.

Later!
Mr. Ed

 

To get the right carb for your vehicle, a number of factors need to be known as others have stated, e.g., lift/duration of the cam, type of transmission, tire size, the rear gear ratio of gears you plan of installing, vehicle use, etc.

I went through this exercise when I put a high-performance engine in my ’56 F100. Holly does a great job of suggesting the right carb provided you have the stats; higher cfm is not always better. You can call Holley’s tech line and they will give you an answer while on the phone.

 

RPM is extremely important . The lower the rpm you will use the smaller carb you need as the faster air flows the better air-fuel mix . My 500+ hp 408 stroker calls for a 580-600 cfm carb because of the 5500 rpm max it's built for if I punch in ( carb size calculator ) 6500 rpm it suggests a 700 cfm . One of the biggest mistakes made is too much carb .

 

Ditto what EBEAR said. Too much carb will cause loss of bottom end torque, performance and drivability. Here is the Holley carb selector: https://www.holley.com/products/fuel...s/carburetors/







.

 

Possible upgrade from 2 bbl. to 4 bbl. suggestions.
Update on specs:
302, balanced, headers, ported to gasket sizes, cast iron heads year unknown, stock pistons, hydraulic flat tappet Crane cam 260/260 duration & .456/.456 lift, 2 bbl. Holley on stock manifold, C 4 transmission, 28 1/2" dia. tires and stock F1 rear axle.
Also suggested rear axle ratio.
Hope I have everything needed.

 

I too have a FT-302, C4, 9" with 3.50 R&P, trac loc, 295/50/15 tires Edelbrock 600cfm performer carb, cam, intake, and heads and Im very happy with it's all around drivability on the highways, freeways, and occasional green lite hammer drop.

 

When I built my 289 for my 49F1 with a c4 i bought one of summit racing's 600 M2008 Carburetors. It run so good out of the box on the dyno machine i bought another one for my 66 Plymouth sport fury with a 383 and i have always used edelbrocks before but give the summit carb a look and the price is good too.

 

Based on RPM's I guess you will be running and everything else you mentioned you will not notice any difference in any of the dual plane manifolds out there. Do not run a single plane manifold for your set-up and as far as carbs are concerned nothing bigger than a 600 cfm. Any of the carb manufactures would be fine but as far as parts availability and ease of tuning goes you can't go wrong with an Edelbrock. Holleys are great also but require a little more knowledge for getting the most out of them. If you plan on driving it a lot you might consider fuel injection, FItech makes a good kit for not a lot more that a name brand carb. Here is a link.
https://www.summitracing.com/nv/part...0003/overview/

 

You'd be hard pressed to go wrong with an Edelbrock Performer intake and a Holley 570 Avenger carb. With the relatively mild setup you have, any decent dual-plane 4-bbl intake and a <600 CFM carb with vacuum secondaries will work well.

I prefer the Holleys, but the Edelbrock is a good carb as well.

 

I agree. The Summit Carb is a very good carb for the money, and it uses Holley parts, so parts are not a problem.