Author Topic: Which Q-jet to build?  (Read 1398 times)

Offline JasonM

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Which Q-jet to build?
« on: December 28, 2020, 08:41:43 AM »
I have 2 Quadrajets here and I am wanting advise on which one to rebuild. The end result is going on a 318 Mopar, (stock cam, 1.88 intake valves low compression 180 gross Horsepower)

My interest at this moment is primarily drivability, and fuel economy. The car has 2.2:1 rear axle gears and it weights in around 4000 lbs. I may swap a 360 in at some point, but for now I would like to see if I can get 22-25MPG out of it on the interstate as I loaf along. All work at this moment is directed towards fuel injection like performance out of a carburetor.

Of my two carbs, one is a Mopar carb linkage.  It is a 750CFM casting  17085431. This carb will need throttle plate bushings, and only has the rear choke pull off. it also has a weird tab in the secondary baffle on the choke housing side. I assume this is for Mopar specific fuel distribution challenges?

The other is an 800 CFM casting with # 17059247 on it. Both casting appear very rebuildable, and i'm wondering if one is a better place to start than the other?

Offline old cars

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Re: Which Q-jet to build?
« Reply #1 on: December 29, 2020, 02:26:42 AM »
Both of those would do a good job , they both have adjustable APT, so remove the plug to access that. The 800 cfm would make an excellent performance carb on a larger motor.

Offline Cliff Ruggles

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Re: Which Q-jet to build?
« Reply #2 on: December 29, 2020, 04:17:16 AM »
The best choice is the later carb with the correct linkage.  They are excellent and mate right up to what you are doing.  It should be an electric choke SMAB model. 

Bushings for the primary shaft are a good idea for any build.  I can supply a bushing install kit and rebuild parts, plus tuning parts to dial it in exactly for the engine if/as needed......Cliff

Offline JasonM

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Re: Which Q-jet to build?
« Reply #3 on: December 31, 2020, 06:27:55 AM »
The 750 sounds like a winner for this application.

Thanks Cliff, I will get my shopping list together and place an order.