I'm installing new Edelebrock dual quads (if they ever get here). The linkage I have been running looks to be of sixties or seventies vintage. It works just fine and I planned on still using it but then I thought there is better out there and so was wondering what advise I could get from the real users and experts on this, not advertising hype from the builders of such. So any suggestions and help is of course really appreciated. Edelebrocks looks pretty nice, but there are others that I don't know about out there also. I'll include a shot here of what I have been running, (don't laugh it seems to work just fine, but lives in a time warp for sure.)
What's wrong with straight linkage? Have done several and they run great. ( Thanks to Carbking's website ) LINKAGE SETUPS - STREET There are basically two styles of linkage: (A) solid, and (B) progressive. Solid linkage has all carburetors operating simultaneously, while progressive linkage utilizes a “primary” carburetor which functions all of the time, and one or more “secondary” carburetors that do not function until certain criteria or met. This criteria may be: (A) a certain RPM, (B) a certain opening of the primary carburetor throttle, or (C) a certain value of engine vacuum. And the intake manifold MAY REQUIRE solid linkage. To run progressive linkage, there MUST be equalization ports connecting the plenums sufficiently large to feed the cylinders not directly connected to the plenum of the primary carburetor(s). This selection will cause as many arguments as the brand of carburetors used (later). FOR BEST STREET PERFORMANCE, VERY DIFFICULT TO BEAT SOLID LINKAGE! Historically, the first (I think) progressive linkage setup was the 1941 Buick compound carburetion. Because of the lack of normal driving performance and low fuel economy, many (most?) of these compound carburetion systems were removed, and replaced with single carb setups. And in fact, Buick totally discontinued the compound carburetion after only two years. Fast forward to the mid-1950’s and the horsepower wars, plus the emergence of local dragstrips throughout the country. The racing sanctioning bodies often would allow internal engine modifications (camshaft, compression, etc.) but REQUIRE the use of the original carburetor(s). Thus the car manufacturers would offer twin 4-barrel setups with progressive linkage so that they could use carburetors THAT WERE TOO LARGE FOR NORMAL DRIVING. During normal street use, the engine would run only on the primary carb, and engage the secondary carb only under “spirited” street driving; BUT the larger carbs were present to provide sufficient airflow for engine modifications of larger camshafts, increased compression, etc. Street drivability with progressive linkage will never be as crisp as using solid linkage.
I have tried both, and straight linkage is more responsive by far. If tuned properly just as good on fuel.
Correctly SELECT and tune the carbs, and straight is better on fuel. Far more important than straight or progressive linkage is the selection of the carburetors. Jon.
I did not say there is anything "wrong" with his current setup, just another, and cheaper, way to do it.
I agree with above, there's nothing wrong with what you have now. To me it fits the style of the old hemi and carbs.
I made my own. I've run progressive and solid. If the car is light enough and tuned right you can't beat solid.
If you want a more progressive control of the throttle even on a straight linkage you could put a progressive cam for the cable on the carb. It has a large radius where the cable lies at small throttle openings = a small cable movement turns the throttle shaft a little, while the "full throttle area" of the cam has a smaller diameter = the same amount of wire pull gives a bigger change in how much the shaft turns. Gives you more precise control on small throttle openings, without causing you to have to move the pedal very long to get all the way from idle to full throttle.
Ah shiiiiiit!!!!!!!!!!!!!!!!!!!! I answered with a long post about how much I appreciated everyone who answered this, did a lot of research on the carbs, intake, suppliers, and decided to stay with what I have, went to post it, and wasn't log in. Went to log in and blew the whole post. So thanks again everone, at least my research gave me a great education
Ctrl-A followed by ctrl-C are great keyboard commands on sites that does that, after you write the text but before trying to post it. (First one marks the entire text, second copies it, if you lose it you just paste it again using ctrl-V.)
With the Edelbrock 2x4 linkage check the Heim or Rod end joints if there is a plastic insert between the casing and the ball swivel and your engine overheats for a period of time the plastic will warp and your throttle will stick and you will have to blip the gas pedal for it to go to idle. From then after when your engine warms up on warm days it will stick on cool to cold day not as bad, the fix are new Heim joints the old style metal to metal, It took me 6 mouths to figure out and it was no fun going anything over 30 mph or faster and taking foot off gas and the sucker keeps going
I'm with Buck. The Edelbrock linkage works nice but is bulky and just doesn't look right on early style cars. After years of running progressive linkage I'm becoming a Carbking convert. After some tinkering, my roadster responded well to direct linkage. My Olds 324 will get 2 x 4 with direct linkage. A piece of stainless rod, two nice Heim joints and some nice bolts, what could be simpler.
So, correct me if I'm wrong, but if making the transition from progressive to solid linkage, both carbs need the idle circuit and air/fuel adjustment screws, right?
Yes.... I idle on both just like the 245 & 270 hp SBC's and like them at about 1/2 throttle on the rear carb the front comes in and has a much quicker ratio making both wide open when the foot feed hits the carpet.. It has been working fine for almost 5 years....
If one uses straight linkage, VERY EASY to make your own. If one uses progressive linkage, fairly easy to make your own. Much of the enjoyment of owning and modifying vehicles is doing the work oneself. Jon
If, you'll excuse my ignorance, Heim joints? (I seem to say that a lot these days, turning 80 this Friday and I use that excuse a lot also), what is Heim joint? Pic please.
^^^^^^^^ Larry its also called a rod end bearing again if your joints have a plastic insert, throw them away it is very DANGEROUS when you are not expecting your throttle to stick got new one's at ACE is the place.
I have three cars with 2x4 setups and all with straight one to one linkage, all with heim ends and brass bushings.
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