hello I have gave up on the efi converion and desided it be easyer and cheaper to go carb. I like to know what size carb I should run on a 302 bored 30 over with a 2040 crane roller cam 220 dur @.050 int&exh .530 lift int&exh 110 lob, cam's rmp range is 2400-6000rpm also gt40p heads mildly ported and polished. thanking of using the rpm airgap intake.
Gears? Tranny? Stall? If the car is an automatic with stock stall and highway gears, definitely a vacuum secondary carb in the 600-650 range. If you got a stick and some steep gears, a double pumper in the same size range would be good.
I will be using a c4 trans and a 2500-2800 stall I have not desided on what gears yet some where in the range of 380 to 411. thanks
The Edelbrock carbs kick ass but I don't like the location of the fuel line inlet. It's on the rear side. Why couldn't they locate it in the front like most other carbs? I'm probably gonna just buy another Holley, as it's pretty much a direct bolt-on and even comes with the Ford Kick-down linkage, whereas I heard that you have to buy that separately for the Edelbrock, not to mention the fuel line adaptor ($45.00!) and throttle cable bracket adaptor as well...
Believe it or not my 5.0w/b303 rollercam,ported e7 heads and stealth intake really liked the holley 700 mech secondary dp,had 3500 stall,3:55 gears.Got better times with it than a 750 vac secondary or 600.Kinda rich idling though but I never tried jetting or anything,coulda probably fixed that but it ran good otherwise.
Good street manners and semi-liveable economy, 750 vac (3310) is simple and popular. It runs off the primarys unless it needs to open the secondarys. The primarys flow about the same as a stock 2v carb, so it's not overcarbbed. With a single plane intake I have had extremely good luck with 700-750 DPs. Gears and tranny type didn't matter as much as the single plane intake IMO. Even with a 218 @.050" cam, C4, and 3.00 gears, a single plane and 700 DP gave the best performance. Our cars are on the light side and our engines like to rev higher than most others, so overcarbbing is hard and single plane intakes work great. Dave
I also like the 750 Holley. Vacum secondaries for street and some street class drag racing. Mechanical double pumper 4150 for all out racing and larger cam and stall. Make sure the manifold you have will accept the spread bore carb if you decide on it.
I have a adapter plate I used a few years ago my camaro with a Q Jet card I would thank it would work the same for the holley also I hope. Also i forgot 4011 holley is a Double pumper also
I didn't get the spreadbore holley i was out bidded but a friend of mine gave me a square bore 4777-2 2808 holley that needs a rebuild:bananaman I looked it up it states its a 650cfm 4150 Double pumper. My my dad ran a 650 DP on a 302 he had in a 67 mustang and he said it would flood the engine so he used a Q-jet and it would tot the front wheels though 2nd gear. So you guys running a double pumper on your 302 what size jets are you using and asselerator pumps? and any tricks my may know. thanks Jim My engine 89 302 bored 30 over speed pro H273CP. flat top pistions 97 gt40p heads that will have A mild porting & stock valve size & shaved 40 thousands for a 10.5 compression Crane 2040 cam 220 duration at .050 110 lob center .498 lift int & exh Crane 1.7 roller rockers to give a .529 lift old style Edelbrock 289 torker intake Holley 4777-2 2808 carb
I think 600-650 vacuum or mechanical would be plenty. In general, lots of people choose way too much cam or carb for a street car. Just my $.02. If a race car, and tuned well, I'd jump over the 700 cfm barrier. Not on a street car.
From experience I would not reccomend any form of a 650 Holly. Some have good luck getting them to work perfect but we have not and saw too many others that have problems with them. The last problem was in a light car at 2000 lbs with a 5L roller motor, world heads and B303 cam and 5 speed trans. With a brand new carb, this engine would go extremly lean at about 5 inches of vacuum and hesitate badly until it picked back up and began to wind on the secondaries. Heavier secondary spring did not help It was found that the problem had nothing to do with the accelerator pump, squirter size, main jets or power valve by changing there sizes and values. These systems were all investigated, changes made, with no solution to the problem. Richening up made the problem worse. The problem is also seen on an oxygen sensor so we know it is a severe lean condition for that short amount of time. My position is that the internal passages or bleeds are incorrect or faulty for the very light combination of car and engine. The engine winds so fast that something in this carb cannot supply fuel all the way down to near zero vacuum drop at the carb. This was determind with a vacuum gage, repeatedly, while the car was being driven by my son, so I could see what was going on for him. The two insturments confim togather at the same time a lean condition. He thought it was simple fuel starvation but this showed it was something quite different after all the work he put into trying to solve the problem. In the past I have had and worked up a 600 vacuum secondary that along with fine tuning the ignition curve resulted in nearly the throttle response of fuel injection on a lightly modified 302 in the 270 hp range. Don't go any larger than 600 because the engine draws less then 550 cfm at 6000 rpm when efficiency losses are figured in. Those that are after the most wide open power will benifit from larger flow capacity but only at wide open and near zero vaccum drop. With normal driving, the larger flow carbs tend to kill throttle response where you drive most of the time.
in my honest opinion... you should put an edelbrock 600, vacuum secondary carb on it. there are a lot of people who are really loyal to holley's and i wouldnt want to offend them. (probably will) the holley is only easier if thats all you are familiar with. if you arent... you will be if you drive it a lot, or see constantly changing weather conditions. i have used both. the holley delivers better fuel economy and a better kick "IF/WHEN" it cooperates. however, ive found the edelbrock to be more reliable, smoother, totally consistent, and easier to tune. i find the holley is difficult to work with, but i guess its just what youre more familiar with. i see some are recommending an even bigger carb than a 600, or double pumpers. i have to question if a small ford V8 really needs that much carburetion on a street driven vehicle. id have to assume that the vehicle is pretty radical to require that. regardless... on a street driver.. id recommend an edelbrock 600. be sure to buy a strip kit with it. a little pricey, but it makes fine tuning a cynch. as for the transmission kickdown... if its an auto and you go the edel route.. you'll need to buy the trans kickdown attachment. (approx. $20), and the adaptor plate/kit for accelerator cable relocation. the fuel bowls on the edel are on the sides as opposed to front and back. i will say though.. that edelbrock well scienced this out, and it all fits perfectly, and mounts easily.
