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73-87 Chevy _ GMC Trucks => Performance => Topic started by: MyOldScottsdale23 on April 22, 2013, 01:23:05 pm

Title: Which carb?
Post by: MyOldScottsdale23 on April 22, 2013, 01:23:05 pm

I have ordered a 330HP/350 crate motor with vortex heads for my 1985 Sierra 4x4. I am currently running the original Quadrajet and it is run down and ready to be overhauled. So I need some advice on what would be the best carb for my new engine and truck. I am also running the turbo 400 trans with kick down solenoid. So no cable. I'm not sure if that matters. I was thinking the Holley 600 but a specific part number would be awesome. Thanks for any help.

Title: Re: Which carb?
Post by: Fairlane514 on April 23, 2013, 07:01:36 am

Keep the quadrajet, its a good carburetor. They can be very good on mileage  and when you get into the secondaries you have 750 cfm. There is a number stamped on the drivers side of the carb just behind the throttle linkage. Its a vertical number, you will need this when ordering the rebuild kit.
The biggest problems with the quadrajet are the plug wells, loose throttle shaft and warped air horn. The first two issues are easily overcome, the third (warped air horn) is a little more difficult.  Most rebuild kits don't include the throttle shaft bushings (some have teflon tape) but you can find them on ebay with the special drill. The kits include the brass bushings and small screws for the blades. Be sure and grind down the "staked" part of the screws BEFORE attempting to remove them, they will break off otherwise.

Title: Re: Which carb?
Post by: MyOldScottsdale23 on April 23, 2013, 11:52:28 am

Thank you!

Title: Re: Which carb?
Post by: Irish_Alley on April 23, 2013, 04:33:51 pm

x2 on what he said keep the quad. first thing most people think is they need to get rid of the quad but its really a nice carb

Title: Re: Which carb?
Post by: Jason S on April 23, 2013, 08:10:33 pm

Keep the Q-jet.

Besides being a very responsive carb when properly tuned, the center float is so much more friendly off roading than any Carter/Edelbrock or Holley that I've run.

Title: Re: Which carb?
Post by: MyOldScottsdale23 on April 24, 2013, 07:46:05 am

Jet Performance has two different kits for quadrajets. I can't get to my truck to check the part number on my carb until tomorrow. Does anyone happen to know which quad is on a 1985 gmc 4x4? I'm just tryin to order te kit in time to get it here by the weekend. I guess I could order both kits if I had to.

Title: Re: Which carb?
Post by: Fairlane514 on April 24, 2013, 08:59:06 am

It depends if its the original carburetor. The number will determine that. You should check the front linkage/throttle shaft and see if its loose or sloppy, if so it can be a source for a vacuum leak.