Hello I m looking for a 2bbl carb, coz stock its broken, i got 302 from 75' Im considering what to buy 2bbl or 4bbl but im not sure whitch should I take. If i choose 4bbl what kind of parts i need to buy. If I take 2bbl its only stocks carb's or they also are little improved from stocks carb's?? Choosing 2bbl i will not buy a intake right? Car will be daily driver. Will be nice if car will be drive better than stock factory car. Can you put me links or names products what i have to search for?
stock carb got how many CFM? i m thinking about: http://www.holley.com/0-4412C.asp Is a better choice than stock one??
Stock carb cfm rating depends on the throttle bore diameter. That can be found on the drivers side of the fuel bowl, behind the accellerator pump linkage rod. Numbers I've found on stock Autolite 2100's are: .98(190 cfm), 1.02(245 cfm), 1.08, 1.12, 1.14 (300 cfm), 1.21, 1.23 (356 cfm). The largest was a 1.33 (424 cfm) The Holley 350 is a good size for a stock 302.
A rebuilt 1.08 V 2150 motorcraft or a 1.14 V 2100 autolite would make it run the best if it is stock. If you want a 4 barrel, buy a smaller one (under 500 cfm). Then you can get a 4 barrel intake from an old fox body mustang for cheap.
The Holley 4412 is a 500 cfm carb that was originally made for racing only engines in the 390 CU" range of specific 2 bbl classes. If you use this carb on a 302 you will have to adjust jetting to get it lean enough to operate well on the street. It will provide enough air and fuel for power but it will never be an economical carburetor. You will get much better over-all performance and economy with a small 4 bbl Holley like the 1850.
I agree with most of this, but the jetting part. I have one now on the roller 5.0 in my 89 Ranger and the jetting is not too rich. Motor is a bone stock Explorer motor. Actually the jetting will be a tad on the lean side due to the larger throttle bores and correspondingly weaker vacuum signal. The 500 is exactly half a 750 DP 4 bbl. It did run better with the previous setup of a Holley 570 Street Avenger on top of a Ford A321 intake, started easier too (which supports the idea that the jetting is leaner with the 500), idled without a choke (but the 500 idles as well without a choke) Last one I used was on a mildly built 400, it was easier to start than the Autolite 2 bbl it replaced. The 500 is a great low buck carb, but he'd be better off with the smaller 350 Holley 2 bbl.
the 350 CFM (7448) uses #61 jets, .031" pump shooters and a #85 power valve. It is a street performance carb. The 500 CFM (4412 C & S) uses #74 jets, .028 pump shooters with a 50cc pump, and a #50 power valve. They are noted as, "used only for competition / off road vehicles only..." On a stock 390 I have had to reduce the jets to #69 and increase the power valve to 105 in order to get the carb to supply proper mixture and streetability. I am not argueing with your own experience as each engine is different and there are cases where the internal parts of the engine or the manner of operation could be compatible with the factory settings. You state that the 500 CFM carb idled better without the choke which agrees with my experience but I will add that it was easy to flood the engine with 500 - even without using the choke.
It's easier to flood it due to the larger accellerator pump. You get nearly twice the volume of fuel by pressing the go pedal once as opposed to twice with the 350. I remove the chokes on all my Holleys.
Hi Hi. I have a 302 Stock Hei distributor. I´m trying to decide between. - Holley 2bbl 350cfm. -Holley 2bbl 500cfm. - Holley 4bbl 600cfm. - Weber 500 Edelbrock 4bbls I´m looking for the best performance and economy. My Mav it's a daily driven.
The Holley 350 2 bbl is what you want. You won't see any difference you can tell by doing a 4 bbl swap in fuel mileage. Plus you'd have to factor in the cost of swapping intakes.
Thanks baddad457, You are right. I´m gonna choose the 350. Is the weber 500 edelbrock a good option?. I´m gonna buy the 350 but I wanna know if the 500 is economy. I have a good price for a deal. I saw an adaptor 2bbl to 4bbl. Thanks for the advice.
Forget using a 2 to 4 bbl adapter. It's a bandaid approach to carb swaps, good only in an emergency. Never used an Eddy carb.
