New Carb.

Spence

Junior Member
I have an 83' K10 with a 350. It has the rochester quadrajet carb. I was planning on replacing it. If I replace the factory carb. with a holley or edelbrock, would it have much of an affect on the gas mileage or would it be about the same? What would the price difference be between the factory replacment and the performance carb.?
 
Depending on the condition of your current carb, the gas mileage would probably go down with a replacement Holley or Edelbrock. These carbs typically have larger primaries than the QJet and are not designed for economy. The replacement QJet would probably be about the same as what you have, but they are a standard replacement for many different engines made by GM, so may not be calibrated specifically for your engine.
Have you considered a high-quality rebuild of your original carb? It was designed by GM engineering to match your engine combination and will most likely provide the best economy and drivability.
Jeff
http://www.jeffsclassics.com
 
OP
S

Spence

Junior Member
Jeff,

I thought about rebuilding it, but it has already been rebuilt once. Would it be worth rebuilding it again? The engine is not the original one. It came from the factory with the 305 and the guy I bought it from rebuilt the 350 and dropped it in.
 

fran

Junior Member
I JUST INSTALLED A EDELBROCK 600CFM W/ELECTRIC CHOKE. RUNS GREAT. AS FAR AS THE GAS MILAGE I COULDN'T TELL HAVE ONLY HAD IT ON FOR A COUPLE OF DAYS. IM AFRAID TO CHECK. AS FAR AS COST IT WAS 230 FOR CARB, 20 FOR ADAPTER PLATE, 20 FOR NEW BREATHER AND FILTER, FUEL LINE AND FILTER 20=290. A EDELBROCK REPLACEMENT Q-JET WAS AROUND 550, I SPENT LESS AND AM VERY GLAD I DID. LET ME KNOW WHAT YOU DO.
 

fran

Junior Member
BY THE WAY MY 350 HAS BEEN REBUILT A FEW YEARS AGO AND THE GUY I BOUGHT IT FROM SAYS IT HAS A STEEL CRANK AND A RV CAM.
 
OP
S

Spence

Junior Member
Price is the reason that I asked that question. For a replacement factory carb, it would cost around $500. I know that a Holley or Edelbrock is cheaper, but I was told that it would kill your gas mileage. Not sure what I will do.
 

fran

Junior Member
I WAS ONLY GETTING 7 MPG ANYWAY. AND THAT WAS WITH THE PLOW OFF THE TRUCK SO I FIGURED FOR THE PERFORMANCE INCREASE WHAT THE HELL GAS IS CHEAP(HA HA).
 

MTCK

Senior Member
Location
Fairbanks AK
One rig I have has is a 4x4 '83 half ton with 700r4, 2.73 gears, 32 inch tires, a 305 with about 100,000 miles, that still gets up pretty good, with an edlebrock performer 650 carb and dual plane intake that gets just as good as mileage as the old quadrapuke, steel EGR intake did, with a little more power, and better throttle response. Now I'm running Hedman Headers with dual 2.5" pipes and flowmasters. I'm sure that helps a little too........
 
OP
S

Spence

Junior Member
MTCK,

If you don't mind me asking, how much did that Edelbrock 650 cost? Cost is my biggest concern. I need to do something soon because the carb. on my truck now is in bad shape. It drinks gas like crazy.
 

MTCK

Senior Member
Location
Fairbanks AK
I was wrong. I have a 750cfm on mine, which is a bit much, but I was planning on dropping in a hot 383 at the time, so it seemed like a good idea. I bought the carb from Summit Racing for about $210. That's a manual choke model. Summit has an online cagalog at http://www.summitracing.com and the prices are : 500 cfm manual choke - $206 600 cfm electric choke - $228 600 cfm electric choke and EGR $250 600 cfm manual choke - $200 (good bet) 750 cfm electric choke is $270. Good luck. Also I think you'll need an adapter plate to put a square bore carb on your spread bore intake, unless you replace that too. (non emission dual plane edlebrock performer is right around a hundred bucks.) Good luck
 
OP
S

Spence

Junior Member
Thanks for the information. I'll have to check that out. I'm not quite sure how to tell the difference between a manual and electric choke. I have to bump the accelerator to turn off the choke, does that mean its manual or not?
 

84'GMC4x4

Member
no, if it was manual you would have a knob in the cab that you would have to pull out to choke it when the motor is cold. like a motorcycle if your familiar with those, except that a motorcycle choke is usually slid up & down on the handlebar not a knob you pull out, but you get the idea.

with electric, the choke mechinism is pushed on automatically when you turn the key on. that is why you have to pump the pedal once before starting, the choke mechinism is being pushed on but there is a little hoobie that it catches on and by pushing the pedal you free it up to slide by, thereby opening the choke.

that's about the best discription i can give you of what happens, if you have a friend turn the key and press the gas pedal, you'll see what happens. it's much easier to understand when you see it happening.

greg
 
At some auto parts stores you can trade in your old QJet carb for a rebuilt QJet - Holley rebuilds them. I have one on my truck. At the store, though, have them look up your vehicle to see if the carb you have is the one you're SUPPOSED to have, based on year, electronics, emissions, and engine. If not, go with what their books show if you want to stay something close to "design specs" for your vehicle. There's a pretty steep core charge if I remember right, but you get all that back. I think you can get one for less than $200.

Just a bit of a disclaimer here - the reason I went this route is because I don't know hardly anything about carbs - if my carb goes "funny" I don't know how to fix it and I have to take it to someone (I know a couple guys here that build race cars for the local dirt track, and they know carbs!!)

Anyway, it's just something else for you to consider.

Todd
 

79scotts

Junior Member
Spence,

I have a 79 K10 with the original 350 in it. I recently replaced both the Q-jet and the stock manifold with an Edelbrock Performer manifold and Edelbrock 600cfm squarebore carb. In addition to adding a ton of hp and torque, it actually improved my gas mileage by about 3mpg. The carb was pretty well dialed in out of the box. The only calibration that I had to perform on the carb out of the box was to add stronger calibration springs which is much easier than anyone knows. The manifold is a big improvement over stock and will improve midrange torque considerably so if you have a spare day you might want to replace both, it's worth it.
 

Top Forums

Similar threads

Similar threads

Top