73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Fuel Systems and Drivability => Topic started by: lukieg on January 13, 2012, 09:16:38 pm
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Ok so the other day i realized my holley had a small fuel leak.. not surprising, I pulled an old q jet out of the barn and slapped it on.. its missing some parts and its only running the front 2 barrels. Its on a 366 tall deck. It has literally doubled my mileage. It has crazy low end throttle response and it really doesn't seem to fall on its face when you nail it.. i will admit, it doesnt pull nearly as well as the holley but all things being considered its pretty decent. I was wondering.. I need to drive the truck i was actually considering a 305 swap due to the fact im going to school in a month and i need to drive a fair distance daily. Would a dual jet with a home made (assuming none exist) work ok on this engine?? I know a quadrajet nets the best mileage but this is so much better I actually enjoy driving it again.. the mileage before was devastating. Any thoughts.. a dualjet 200 or 165 would fit my adapter.. anyone have one for sale? trade for a good holley :) any input would be helpful, thanks
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So your saying the q-jet is only working on the front bores, and the secondaries are not working ? (meaning you can not suck down gas when you stomp on it). Why not swap to a 305 with a 2 barrel q-jet if you are happy with the power your getting now.
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OK I bet that old q jet came off a car rebuild that old q jet and run it it sounds to me like it is the right c f m for your ride.I can't believe you got that Lucky.
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The qjet is missing alot of parts... swapping to a 305 is alot of work... and m y point was.. im not losing much power.. only a bit at wot.
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The front 2 jets on a qjet should be no problem, I ran that way for years with the secondaries unhooked.
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What displacement engine did you run the unhooked qjet on? I cant seem to find a reman or core qjet 200.. i believe thats the 800 cfm primary version, i thought it might work a little better. Anyone know of a place that might sell them.. aside from napa? Thanks
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What displacement engine did you run the unhooked qjet on? I cant seem to find a reman or core qjet 200.. i believe thats the 800 cfm primary version, i thought it might work a little better. Anyone know of a place that might sell them.. aside from napa? Thanks
350 engine in a 1972. I will look on my shelf to see if I have anything. I seem to remember an old dual jet on there from an Olds 260 CID. I will suit up and take a trip out there to the shed.
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Here is the two I have
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Thanks man :) thats wicked.. i wonder how much bs it would be to rig that e2me one to a holley intake... hmm... lots of low rpm torque.. whats the cfm on one of those dualjet 210? Oh and more important.. where do you reside, and whats she worth to you? Thanks again.
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Oh I know this is a stupid question but im not much of a thinking mind.. a small carb wont cause lean conditions will it?? It will just limit the total power at an rpm above what the cfm the car can supply right??
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car=carb
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You would have to play around with the jets, no knowledge on the CFM but I bet that info is available on the net somewhere. PM sent.
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http://oldcarmanualproject.com/manuals/Carbs/Rochester/DualJet/E2M/service/index.htm
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perfect.. im just looking into materials for an adapter.. would the stock jetting work? The jets are all in relation to fuel and air correct?? so would it be jetted already for the cfm it is? These things confuse me.
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I have only done this once and I had help. Back in the early 80's I had a 72 Chevy pickup with a 350 engine. I played around with Q-jet and one like pictured on bottom. Where I worked at the time had a pile of carbs and I played with the jetting and would drive the truck a couple of days, check the plugs and the exhaust pipe tips until I got a good balance. I ran it a tad lean and had an ever so slight hesitation but that netted me right at 16 mpg. Best I could do with the q-jet was 14. I ran an adapter plate similar to the ones I am selling in the classified section. The truck engine was a stock 350 with about 100K on it, running P235 75R15 tires a TH350 and a 3.08 gear out back and dual 2" exhaust all the way back with quiet mufflers.
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the 2gv got better mileage the the qjet?
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Is the dualjet 210 base plate different then the standard qjet? Does it match anything else, or is it a unique pattern? Thanks again
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the 2gv got better mileage the the qjet?
Yes after I found the right combo. Best I could do with the q-jet was 14. Of course I was 21/22 back then and probably stuck my foot in it more than I should. I should have unhooked the secondaries and tried that but once I put the 4 bbl-2bbl adapter plate on that engine I never went back. Back then my commute was 100 miles round trip a day and the 2bbl did a great job. I taught my wife how to drive in that truck. I remember the PS box had a minor leak but enough to need to add fluid once a week, then the high pressure hose sprung a leak. I didn't have 2 nickles to rub together but I had a parts truck around the back of the barn that had a good manual box. I converted it to manual steering and had one less V-belt to worry about. Those were the days...
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Is the dualjet 210 base plate different then the standard qjet? Does it match anything else, or is it a unique pattern? Thanks again
Never messed with it but here is a picture of the bottom. Looks to me you are gonna have to fabricate some kind of adapter plate.
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http://www.fireballroberts.com/Fish_Story.htm is some interesting reading. Every once in a while I will search eBay for them. I worked with a guy who was a chemist and actually very intelligent. He ran a nasty old mid 70's Buick with a 350 and one of these Fish carbs on it. He was getting between 30-35 mpg with it. Then he put a smaller one on a Pinto and was getting in the high 40's.
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where can one get one of these super efficient carbs.. any still in production? I would be willing to try one.
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where can one get one of these super efficient carbs.. any still in production? I would be willing to try one.
I have no idea, I see them from time to time come up on eBay but never tried winning one.
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The front 2 jets on a qjet should be no problem, I ran that way for years with the secondaries unhooked.
If you are going to school and on a budget, I think I might leave it as is and enjoy the driving like you said. It will not cause any realiability problems.
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I know a quadrajet is a better option.. but its soooo hard to stay out of the secondaries.
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How far does one have to depress the petal to make the secondaries on a qjet open?
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Depending on adjustment, usually about half way down on the gas pedal.