Quadrajet Mystery and questions

In August, I picked up a 1983 GMC C1500 w/ 305 (H-ESC), 700r4 and 273:1 ratio. Story was it had been parked in a shed for many years with little use by second owner who passed prior to his 90th birthday. Oil change sticker indicated that it moved 400 miles since early 2019, and was told by family they used it for a dump run now and then. The truck appeared to be an unmolested original. After a few months of work, she goes down the road really well. Real happy. Under the hood, it appears to have every vacuum line intact, Air cleaner tubes, etc correct, ESC is working, 700r4 shifts proper. I find that the original vacuum routing label is missing, because it did have radiator support replaced due to a light front right crash (Reight Fender, inner Fender obviously replaced). No big deal.

I thought I would order a carb kit to have ready for spring. Carb # is 17056202. Surprise to me!, looks like carb has been replaced with a 1976 era carb. Unfortunately, I can not find that exact carb number, though I find ones close.... 6208 for a 1976 Buick Lesabre (I think). Not sure I should even order a kit just yet. I have no indication that it originally had an "electronic controlled" carb as there are no spare plugs/wires anywhere. Rock Auto shows the replacement as an M4ME.

Well, the QUESTION really is >>> if I were to take this to a Carb rebuild fellow, what should I tell him to get it to be rebuilt with proper jetting for this 1983? I've done a few 60 mile loops with the truck so far and seem to get about 13mpg max. No cruise, just a steady pedal. I realize the EPA figure claiming 20mpg for 1983 is wacko, but I'm thinking with the overdrive and 273 rear, it could do better than 13... perhaps 16 should be possible the way I drive it.

OR, should I attempt to find an M4ME for any specific reason ? Thanks in advance. I've often swapped Quads around just to make stuff run, but for the first time in my life, I'd like to do a quad right, or as right as possible.

Go here:
Buy his book. It's worth every penny. He has a form you can fill out and he will send you the CORRECT rebuild kit for your carb.
If you call him, he loves to go fishing! Great fellow.

Scroll to bottom. Has carb number/ jetting and rod combos

My 81 350 motor , q-jet# 17080213, has 72 jets, 50m rods, secondary's have DP rod

Wow, thanks fella's. That Cliffs forum looks like I can learn a lot there. And, the PDF will be tonights reading.

I went out in the garage and found a carb off of my old '81 Chevy P30 # 17080204. This looks to be closer at least in age, but it was on 350/auto truck. I do know it was original to that truck and I got decent mileage with it even though it was a 14' Step Van.

I'm thinking this might be a good donor. I think Cliff's might be able to ID the exact jets, rods and hangers the original truck had. GREAT INFO ! Thanks Again !

The buick carb will have a straight inlet fuel line. I thought the thermostat housing on a SBC made it unable to run a straight inlet carb.. i seem to remember trying this years ago and it didn't work.

grummy said:

I find that the original vacuum routing label is missing, because it did have radiator support replaced due to a light front right crash

Click to expand...

77Dmax said:

The buick carb will have a straight inlet fuel line.

Click to expand...

Yep, your right. Carb on it now (17056202) does feed from the left side, so it is Chevy. Another site now indicates Camaro and Corvette.

I have been searching now for what jets/rods may have been in the '83 truck from the factory. No luck yet with something absolute.

Thanks ! Current carb pic is because we all like pic's !

I think that carb is 1976 chevy truck with a 350 engine.I also think @Doppleganger has a rebuilt qjet for your truck. His may be a dual capacity accelerator pump version I dont remember,NBD easy swap either way. You can run the dual capacity as is or add the temp sensor to the water neck and add a power source.

Ricko1966 said:

I think that carb is 1976 chevy truck with a 350 engine.I also think @Doppleganger has a rebuilt qjet for your truck. His may be a dual capacity accelerator pump version I dont remember,NBD easy swap either way. You can run the dual capacity as is or add the temp sensor to the water neck and add a power source.

Click to expand...

Doppleganger said:

You must be registered for see images attach

You must be registered for see images attach

Click to expand...

What year is that carb with the computer plug in piece on the pass side front?
What vender is that one rebuilt from?

.

1985. Was a west coast (Oregon) truck so not sure if anything Cali comes into play. No idea what the plug is (someone here posted it once but I dont remember). The PO hacked all the wiring so I didnt even have a pigtail to look at.

Mountain Man Carb and FI did it. His reviews are stellar. Everyone says its bolt on and go with his stuff. Cost me $320.

Doppleganger said:

1985. Was a west coast (Oregon) truck so not sure if anything Cali comes into play. No idea what the plug is (someone here posted it once but I dont remember). The PO hacked all the wiring so I didnt even have a pigtail to look at.

Mountain Man Carb and FI did it. His reviews are stellar. Everyone says its bolt on and go with his stuff. Cost me $320.

Click to expand...

The plug is for the dual capacity accelerator pump. No it's not California emissions. I wouldn't worry about the plug if I had a truck that didn't originally have one

I ordered one of Cliff's books today. It's something that I am at the point of learning about rather than just flipping carbs to keep it running. I' have had them apart a few times over the years, but not for any "tuning" reasons. I was surprised though that my -0204 does have a brass plug in it to access the APT.... I do recall putting that in, but forgot why it was there until I did more reading. I'll take aim at my #17080204 unit and see what makes these things tick. Truck runs decent so no rush. Great winter project !