What i have is a 302 .mild cam .bore 30 over with a c4 trans.looking for a good carburetor to run with this street cruiser any suggestions. Thanks
I second @Sch****e Engines . I love the edelbrocks easy to tune and no gaskets below the fuel bowl to stain up your intake from drips.
Holley 600 cfm 1850. These replaced the old tea pot stating 1957 and was used by Ford throughout the late 50s and 60s along with the 4100 series....https://www.holley.com/products/fuel_systems/carburetors/cl***ic_holley/parts/0-1850C Autolite 4100 The Autolite 4100 is said to be the best all around street use carburetor ever made. The Summit Brand carbs are 4100 knock offs. I would try to find a remanufactured original. http://www.carburetor-blog.com/autolite-4100-carburetor/
My 302 is a similar build. I started with the 1405 because it came with the electric choke. The 1406 may have the manual choke. However, I had to install bigger jets and springs to get it run well. Its my understanding that the 1405 is jetted pretty lean from the factory, and 1406 is jetted more for performance. Either way, you may want to get some extra jets and springs for tuning.
David, If you're running the stock mechanical fuel pump you will need a pressure regulator if you run the Edelbrock carb. Shouldn't need one with the Autolite or Holley. The voice of experience.
You are going to get answers all the way from Edelbrock, to Holley, to Quadrajet, but my favorite is an Edelbrock. 600 would be ok, but 500 might be better. I've run two 600's on a mild 302 and it was ok, so one would be better. Edelbrocks are just so simple and dependable. don
I've had excellent results with 450 Holley's on small Fords. They will give 'crisp' throttle response around town while delivering good mileage, particularly with an auto trans. They're a bit hard to find these days, but rebuild kits for used ones are still available.
LOL Don is absolutely correct here on all accounts except for the eddy carb. Ok I am saying that just to drive home his point, I personally like the 600 Holley (1850), he likes the eddy and either carb in good shape will make it happen for you. Basically for a driving around car @ 300 - 350 inches 500 - 600 CFM is going to be a good CFM range and if you don't have mechanical secondaries and they are vacuum dependent they will never open more then your motor can handle.
Edelbrock 1403.........500 cfm and electric choke. Or, as someone else suggested, a 450 cfm Holley. One thing has been consistent over the decades.....most people in our hobby install carbs with excess cfm, and usually a too aggressive cam, for the cubic inch size and intended use (street) of the engine they are attempting to improve. A common result is those cases is an engine that performs little better than when they started, though it sounds 'meaner'. Ray
Ray I think that the big cam and carb combo has one simple problem that most guys never figure out, they don't start climbing up on the cam until way past the RPM that the guys want to cruise at. Example, the wife and I had a mustang (plane jane) that someone had stuffed a Boss 302 in (not a "Street Boss") it was useless below 4K but once you got it revved up it was a pure delight to drive. If someone is not willing to keep the revs up they should leave that stuff alone, revved up they only sound good to an engine guy.
I am running a 1406 Edelbrock on a 302 with a mild cam and use the stock mechanical fuel pump with no issues what so ever. Easy to tune with springs and rods. Instructions come with the carb that are easy to follow. Wouldn't have a Holly unless it's a high pref motor that you want every bit you can get out of it, one cough and 'there goes another power valve'[emoji15] Have plenty on hand!
LOL I grew up around hell raisers. All my life I been raisin' hell and puttin' a brick under it. getting back to the question at hand, mild 302 begs for mild carburetor, I don't know if anyone has mentioned it but the autolite 4 bbl that ford used for a long time is a pretty good carb on a cruiser and I have even run them on Chevys.
That's not the whole story; if that were true, you could use a 750 CFM square-bore vacuum secondary carb on any motor. Carbs operate by pressure differential/velocity and the higher the difference, the better they atomize the fuel. The better the fuel is atomized, the better it burns. As carb CFM/venturi size goes up, air velocity goes down, all else being equal. Try using a 500 CFM Holley 2-barrel in place of any same-CFM 4 barrel and see how it performs... around town, these will **** gas like there's no tomorrow no matter how you drive it. So while a 600 CFM carb is a good 'universal' size, more-or-less working on street motors from 300 to 400 CI, it's certainly not 'optimum' for every motor. The Quadrajet (with it's small primaries and large secondaries) is the right theory, it's just the execution that's lacking.... If high RPM max power is the goal, then sizing the carb for that is what you need to do. But expect lower mileage and poorer drivability as the cost. FWIW, I used to have a '64 Comet with a 308" SBF, 4-speed, Torquer intake, and 3.25 gears. I initially used a 600 CFM Holley on it, but low speed performance/drivability was mediocre at best. A switch to a 450 Holley vastly improved both, plus bumped fuel economy up by 3 MPG. The cost was the motor was starting to run out of carb by 6500 RPM, but on the street you were already into felony speeding in any gear anyway, so what the hell....
You can add to that intake manifold choice. If you are running a small plenum a small carb is king, but once your plenum and runner size bumps up there you have to size the carb accordingly. Funny that you use the 500 holly 2 bbl as an example, last time I used that example I got beat up over it. I was correct of course just as you are because you and I both use practical application over theory. Hey while I got your attention let me hijack this thread a little bit. The autolite 4 bbl they used on the 390s what CFM rating was it?
I had first-hand experience with one of those 500 CFM 2-barrels... LOL. I bought a used Ford truck 'with a new carb!' that got abysmal mileage (ok, they weren't that great anyway but this had a 352/stick trans and should have done better than single digits!) that no amount of tuning would fix. Pulled the carb, figured out what I had, stuck a Ford 2100 carb on it and doubled my mileage.... The Autolites basically came in two sizes; 480 CFM and 600 CFM. The small block and early lo-po FE motors got the smaller carbs, anything hi-po or premium-fuel got the 600. If Ford needed anything bigger, they usually got them from Holley. They did build a few larger/smaller versions (a 450 and a 670) but they're pretty rare. Ford stamped the venturi size on each carb body, that's how you identify them. 450 is 1.06, 480 is 1.09, 600 is 1.12, 670 is 1.19. What was interesting is if you went to Ford and bought a new 'service replacement' for the older Autolites, you got either a 450 or 600 Holley....
Thanks for the info on the carbs. I have played with the big holley 2bbls too. I actually have access to a 600 CFM annular discharge, that carb is good for one thing and one thing only, WOT. I look at it this way if I am feeding whatever I am running with say a 600 CFM 4 bbl it initially runs on about half of that or say 300 CFM or I can run a 500 CFM 2 bbl and it initially runs on about 500 CFM. In theory on the same motor the 4 bbl should be snappier and get better fuel mileage.
Carb Questions In the process of doing this on a SBC 350 290 hp. Not a expert on Carbs / 2 questons - Am considering ordering a Edelbrock for simplicity and dependability , read several of the earlier posts. Isn' a 500 CRM a little too small for a 4 barrel mild performance small block rather than a 600 ? Also mentioned above, will need a fuel regulator for a Edelbrock carb if running the stock mechanical fuel pump??Never knew this could be a issue with a mechanical fuel pump ??? Gene
Gene A stock mechanical fuel pump should not override the needle valve on the Edelbrock. Actually while it is not my favorite carb in the entire world I would be looking at a Q jet for the small block. I guess it depends on your intake of course. let me qualify the don't care for Q jet thing here, I don't like working on them they are not a bad carb.
A 500 CFM is big enough for street use, but will limit you a bit at the top end. There's lot of CFM calculators out there, do a search and try several. Be realistic about how you will actually drive the car, dialing back the 'brag factor' will result in better mileage and drivability.
Consider that one cubic inch is one cubic inch. But a cubic foot (the 'cf' part of cfm) is 1728 cubic inches (12x12x12=1728) by extension, 500 cfm is 864,000 (500x1728) cubic inches! Just how many rpms does an engine have to turn in order to exceed 864,000 cubic inches of carb capacity? Granted, that is at 100% efficiency, but even 85% it's 734,400 cubic inches! My math says 4863 rpm at the latter number. Ray
I actually read an article on carb calculators a while back and they said something interesting that kind of goes along with what I have been doing by the seat of my pants for a long time. they say that you have to take the carb suggestion and reduce it by as much as 20%. So lets ***ume that you had a carb suggestion of 700 CFM Knock off 20% and that brings you back to the 550 CFM range. I did reshape my venturies in a 600 CFM holley that I have on the shelf and did some of that stuff that @falcongeorge calls tuning but I made over 400 horse with that carb bolted to a 350 or so cubic inch motor. granted I also did some fine tuning to the intake and some other things, but if I recall the calculator that I used called for a carb in the 700 CFM range as I recall.
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