i tried to read up on some of the other posts the best i could but i'm still kind of lost. Ok so i'm definately going with a quadrajet but which one? i'm building a stock 1968 327.....so should i really stay away from remanufactured? and something about electric versions? help!
Anything with the fuel inlet straight out the front should be correct for your application. I think the side inlet carbs came along in the early 70s. If you are going with a thermostatic choke, you need to be sure your intake has a heat stove built in. Otherwise you'll need an electric choke model.
The ones with the split runners? I guess they're traditional, but there's a reason they stopped makin 'em...
If you want the best bang for your buck, go with a 75- 80 800 cfm 454 truck carb with the 1.21 primaries. The 81 and newer passenger car carbs were electronic feed back models. If you're talking about electric chokes, you won't need one in Phoenix anyway. Lose the whole deal, choke plate and all. Jet it with about 73 to 76 primaries and about a .030 smaller metering rod. Maximize the accellerator pump and give it a few shots and it'll start right up, year round.
800 cfm?! i was thinking more like 600....i want gas mileage not performance and whats wrong with the manifold?!
shoot, I've gotten several early 70's, manual choke Quadraslushes off eBay for $5, rebuilt them for $20, and had a good, efficient, if somewhat mushy carburetor. They'll usually list stamping numbers in the auction, you search "Quadrajet stamping numbers" on google and there's tons of sites that decode them. Find one that is closest to your application and you're good to go! I'm running three vehicles now with Quads and nothing beats having an interchangeable carb for when parts go bad or you need to test something- plus, NOTHING beats a Quad offroad besides injection
Here's what you do then. Pick up a Dual Jet off of a 1975 301 P or a 260 Olds. It'll bolt right on and you'll get great mileage with no secondaries! Seriously , A small primary (750) Qjet will give you good mileage if you don't open it up. Total CFM is irrelevent if you just use the primaries. GM used them on 230 ci OHC Pontiac sixes.
All Chevys had side inlet fuel lines . Caddy's had them too , to clear the a/c compressor. All BOP carbs were straight inlet.
79th and Bethany ."Montebello Estates" Near the canal. How about a factory 305/ 350 aluminum manifold? Should be cheap enough. Good low end torque.
Look here to ID Q jets: http://www.buickpartsdirectory.com/images/clip_image002.gif This code is stamped vertically on the driver's side by the secondaries. You probably want one that starts with the "70" prefix Later "Smog carbs" with too much engine specific tune stuff in them start with a "170" Don't go there, and don't mix the jets and rods from them with earlier carbs either, they are different design. They are all either 750 or 800 but the secondaaries are vacuum operated so they only use as much as the engene asks them for. That's how Cadillac got away with putting a 800 CFM one on a 4.1L version of the Buick V6 I'm running one off a '69 Z28 350 on a 262" V8. Get a half dozen or so $5 or free ones from the "gotta have a Holley" guys and build the one that's in the best shape yourself. I openend up a so-called rebuilt one once and it had been on fire and partially melted inside and rebuilt anyway! Look here: http://www.mako.com.au/buick/html/qjet_tips.htm http://www.geocities.com/n1qcr78/qjets.html http://www.442.com/tech/rochparts.html
Some of the earliest Edelbrock Performers had a blank casting on the front of the manifold that could be drilled for an oil tube. I'm with the other poster that dissed the "Dual-Port" intake; I've never seen them do anything positive for a street engine.
Forgot...I've had good luck with any Quadrajet in the '69-'73 range for street performance. The '65-'68 carbs came with a strange looking needle/seat setup that wasn't the best, and the '74 and newer carbs are generally set up quite lean for emissions.
You might want to check NHRA's blueprint sheets on their web site. Some of the early small block manifolds were very good if you don't mind cast iron. Pete
i have a cast iron intake that came on the motor but i had a feeling that an aluminum would perform better......oh and what about marine carbs? no good?
Park and swap sunday? I've got a Qjet off a 77 'burban out in my yard. AQlso have a weiand dual plane setting here, not a front oiler though. jerry
yeah sounds good, check the sinners board they were talking about heading to some guy's yard sunday afternoon? is that quad anygood? the guy's on here were saying stay between 60's and 73'???????can the weiand be drilled for the oil fill tube?
If you need a book on how to do rebuild here is a good one. I personally know this guy and he knows his shit. Races with Q-Jets all the time too. http://www.cartechbooks.com/vstore/showdetl.cfm?st=0&st2=0&st3=0&CATID=19&Product_ID=2510&DID=6
Offenhauser makes multiple manifolds for the Quadrajet carb. Most people do not understand the design differences of the manifolds and put the wrong manifold on their application and bitch because it doesn't work. Also, most people selling the Offenhauser manifolds do not understand the design differences and recommend the wrong manifold to their customers. The dual port manifold is far superior to the dual plane manifold in numerous ways. An engine at low rpm's does not require as much air it does at high rpm's. But, it does require a higher velocity of air flow in order to run efficiently. This is why the dual plane manifolds makes more torque and horse power at lower rpm's than an open plenum manifold. The restriction of the air, by way of the runner desgn, increases air velocity at lower rpm's. But, the runner design hurts upper rpm performance. Also the runners allow the fuel to be "thrown" out of suspension in the air by centrifical force as the air moves around the bends in the runners. An open plenum manifold does not have the restriction to the air flow as a dual plane manifold has. The dual port manifold is basically 2 open plenum manifolds stacked on top of eachother. The lower manifold is feed by the primaries of the carb. The chamber size is small to increase the air velocity at low rpm's. This allows the manifold to perform excellent in the lower rpm range of the engine. The upper portion of the manifold is feed by the secondaries. The area of this chamber is much larger than the primary chamber. This helps increase air flow at the higher rpm's of the engine, with out restriction. As the two air flows meet at the head, the faster moving air of the primary plenum pulls the air of the slower moving secondaries plenum into the cylinder (similar to drafting as seen in the last Indy 500). Fuel mixture is maintained at the proper ratio during the entire rpm range because there are no runners to create centrifical force. The dual port manifold increases low end torque and fuel economy. The deisgn was even incorporated into some Ford manifolds during the mid to late 80's to increase performance and economy. The dual port manifold, in it's current design by Offenhauser, is not designed for high rpm use (above 6000 rpm). It is designed as a stock replacement manifold. This is where many people use the manifold in the wrong applications. Changes can be made to the divider blade to increase rpm use. The change must be made in a very specific manner to maintain proper air flow. The port divider must not be "sharpened" or tappered. This causes the divider to like a wing on an airplane and increases turbulence in the air flow, which decreases performance. The divider can be machine back in the port, upto 5/8" to increase rpm use of the manifold.
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