I'm having My 327 built to around 300+ horse and I was just given an old covette dual quad intake. Would two 600 cfm carbs be two much? If so could I run restricter plates ala Nascar? Thanks Guys
Chevrolet claimed 270 H.P. on a 283 with those itty bitty Carter WCFBs. If that was true, 300 would be a piece of cake on a 327- without resorting to 1200 CFM.
I'm running old Cadillac (I think) 4bbl Carters on my 283 4x2 set up. If I am not mistaken, they run something like 340 CFM with a moderate Isky cam, which is still more carb that engine needs. My set up runs pretty good after tinkering with it for a while. My buddy John Olsen built builds carb set ups like this for a living, and I'd be happy to hook you up if you'd like.
John's number is 661-951-1862. He's been building hot rods for ever and really knows his way around vintage multi carb intakes. He has an absolutely wicked '34 coupe with a Lincoln Y block that has dual tea-pot carbs AND is Paxton Blown - but it he put the engine together so well it looks like it came that way from the factory! Anyway, tell him Terry Jones gave you his number . . . best of luck with you project
2 Edelbrock 500 carbs would work just fine. It would just some time to tune them properly. I run 2 on a tired sbc with tunnelram without progressive linkage and it runs fine and can still get 17 mpg. Fine tuning WILL make it right
They fit. I had that setup about 40 years ago. Don't know that it worked right but the WCFBs were not easy to find even then.
Unlike a lot of other engines you can get away with overcarburating a small block chev. use a couple of adapters. change metering rods and jets adjist idle screws so it will idle on both carbs. Let them both open at the same rate. A 380 cfm carb is only 380 cfm at full throttle. Same goes for a 600 cfm at half throttle only 300 cfm. If you have too much carb simply adjust the throttle linkage so you Dont get full throttle. I ran two 625 cfm carters adapted to a corvette intake on a stout 283. You just have to keep playing with it but it will work. Old Wolf
The early Afbs have the same bolt pattern most times you will need a adapter. But once i saw some small carters that where a direct bolt on fit. came from a 273 plymouth Vallant. I will look i think I have one if i find it I will take a picture. Randall
Back in 63 I had a 57 Corvette with a new crate motor 327/340. I ran 2 AFBs off a 409 car on an Edelbrock intake on it for a while and they worked real good. Finally went with 1 Holley 4 barrel, too much h***le. Crate short block motor & heads were $350, how many would you buy today at that price ?
An AFB will not bolt to where a WCFB was. Only WCFB's and Rochester's would bolt on. Having said that, if all you want it 300 hp, a power pack 327 with one AFB was 300 hp. A Corvette with a solid lifter cam was 365. I think one AFB on the original 327 intake would be a better setup than 2 of those old WCFB's. A good source for AFB's were 1962 Pontiac's.
I know that you asked about 2 fours. In the 60's, a really good recipe for go fast was a 327 with a Holley and a hi-rise intake, recurved distributor, 30-30 cam or better, 2.5" exhaust. Almost all of those engines ran really well. I appreciate the fact that you want 2 fours. Find the smallest carbs you can and it will work ok.
I'm new to the board here, but have plenty of experience with a 327 with dual quads. I can tell you that a pair of 390's really don't work nearly as well as a pair of 600 cfm units. I ran a pair of 390's in the beginning, but quickly realized that they were way too small. There are some things you have to do to make the idle circuits restricted to work properly (this goes for any multiple carb setup). Once you choose a carb, we can start a different thread on how to tune them. For the record, the pic above is my 65 in high school. It is a 327 with a pair of 600 holley 1851 carbs modified for the dual quads. My car has a 4 speed and 4.88 gears. It revs, but I drive it anywhere- round town, highway- anywhere. I's been on the road since 1992. Last time I took it out I got 12 mpg, which included 2 p***es down the 1/4 mile!
Thanks Guys lots of good info. The main reson I want to run the dual quads is for looks, 2-4s is twice as cool as 1-4 lol and I promised the Guy that gave Me the manifold I would use it on the rod. I'm not so much concerned about hourse power as I am drivability and Im on a shoe string budget so corvette carbs are not an option Thanks again for Your input
/yep all other things being equal a stock small block will out breath out wind other types of the same cubic inch engines say a 292 ford compared to a 283 or a 322 buick compared to a 327 or a 351 winsor compared to a 350 chev. A carb that would be too big for them and have a bog if opened too quickly will work great on a chev mill. In 1973 chev stock 350s had a 850 Q jet from the factory. It all has to do with air flow past the venturis. If you have a good breathing engine it can consume more CFMs of air fuel mix. that is what a larger carb allows. Like it or not a small block chev is one of the best air pumps ever made. Carter also made a 9400 series carb that flowed 400 CFM. I used a 9801 carter avs from a 440 crysler on a 283 +.060 with a factoryZ28 intake 300 horse heads and mild cam in a 63 Pk never had the slightest bit of bog. Had stock dual exhaust very quiet. But when you tromped on it the intake noise was unreal. OldWolf
I may be full of ****, but, seems like my edelbrock 2-four manifold on a small block had two AFB's and it ran on one carb all the time, seems like it was the front one, then the linkage was progressive, like three two's and the back carb came in. One carb had a different arm length. Didn't 426 hemi's run that way too? On one carb then bring the other carb in? I don't think it ran on both sets of primarys at idle and part throttle.I'm pretty sure the old 2-4 manifolds were open plenum.Lippy
helped my friend build a very nice 55 with a 327--lotsa cam, 4 speed, etc--has a Corvette intake, 2 500CFM edelbrocks with transdapt adapters---runs VERY strong and no problems--has been on the street for 3 years now-very sweet setup-I'm getting ready to do the same setup on a 327 in a 40 Coupe
A carter afb and a Qjet have mechanical secondaries so do WCFB and 4GC rochester. They have a air valve in the secondairys. The Afb on 312 fords did have vacc*** secondarys. The very small primarys and large secondairys are what let 850 Q jet and thermo quad carbs work on 340 and 350 engines. So you are saying that the 350 cu in herculies flathead six on my 600 amp lincolin welder will flow the same as any other 350 engine? Remember i stated all other things being equal? Apperantly you dont like the fact that small block chevy engines are good breathing mills. Wish you where close we could have a drag race! i happen to own nailheads pontiacs dodges FE,s Y blocks ect . Everything else being equal a small block will turn more RPM with less trouble then any other production engine. OldWolf
I'm runing two 600 Carters on a Offenhauser intake on a med 350 with 1-1 linkage, get 15 mpg and smokes the tires at will. The only problem I have is a slight bog off idle tromp, if I brake stall it to 1000 rpm up in smoke it goes. http://www.youtube.com/watch?v=uaEZL0opm5o
What? Restrictor plates? It's all out or nothing. LOL! You can run 600's but you'll end up jetting them down. If you're running low gears it'll be alright and jet down. If you got high gears go with smaller carbs.
Actually the mechanical linkage on AFBs and other 4 bbl carbs is a progressive linkage. the front ****erflys are opened ouite a large amount before the secondairys start to open. So if you are running on both at the same time you still get a partial progressive linkage. OldWolf
Holleys won't fit your manifold unless you do you real imaginative dapting. A pair of carter AFBs or a pair of wcfbs would be your best option. I'm running a pair of 450 holleys on the next rendition of my sbc, it maked a little over 400 hundred horse from 355 inches with a singel Holley. 900 cfm will be a gracious plenty for this mill. I would think that with your 300 hp 327 your going to want to max out in the 650 to 700 cfm range.
PxTx, saw your post on the xc-8 style manifold, I bought one to install and i am trying to get as much info on carb sizes and tuning tricks as possible.I am not in a hurry to fix the car until I repair and replace the motor.The car had a 327 in 1974, it has a lame 350 now. I like the high revving 327 so the motor will have to turn at least 7000 grand.The motor will get cam,good heads, pistons,rods,and crank.interested in your thoughts.
Most (certainly not all) Carter AFB carburetors have the same BOLT PATTERN as the Carter WCFB. However, even for the small AFB carburetors, the footprint is different, as the center-line throttle spacing was increased from side to side. Without some form of spacer/adapter, the throttle plates WILL hit the manifold bore on a stock Corvette manifold. We have sold several sets of AFB carbs for these manifolds. We suggest the Carter 400 CFM carburetor. Part number(s) 9400s or 9410s. 9410s superceded 9400s with the addition of an EGR port which may be plugged. The carbs may be used as a "mix-or-match". To solve the footprint issue, we send two of the fiber flanges used on the mid 1950's Oldsmobile Rochesters. Simply bevel the top of each of the 4 throttle holes by approximately 3/16 inch. These carbs were originally sold as replacements for a Chevy 283. The fuel curve is Chevrolet. Normally, you bolt on the two, adjust the idle and the linkage, and away you go. Jon.
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