Technical Quadrajet 700R4 Combo.

Think that pre '87 700's are weaker transmissions

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Check Jeg's, etc for quadrajet carbs, 700R4 OE linkage/cables, and more

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I have a qjet/ 700r4 in my 37 Buick, the carb is an off the shelf replacement and unknown application. before running it I made sure the cable was all the way retracted into the trans at idle, moved immediately with throttle movement, and line pressures were good in all gears. Line pressure should jump up as soon as the throttle moves, I tested everything before driving the car, a trans pressure gauge is cheap. I would get a pic but the car is up on a lift for winter storage. I will see if I have any pics on my computer.

 

1980-1989 350 Chevy and GMC trucks with OD will have the correct linkage on the carb.

 

I don't got a Q jet but I got an AFB with the proper GM linkage. I would trade it for a good 725 CFM AFB. Basically any GM carb for a T350 or 700R will work just fine. They both have basically the same cable.

 

Not a 700r4 but many(maybe all, not sure) mid eighties Cadillac came with the qjet and the 2004r so the tv cable and carb brackets and arm stuff should work.





Some more diagrams to decipher.
Also after you have the setup all ready to go, I would drop the pan and watch the actual valve in the vb as someone moves the accelerator pedal to make sure it is moving the tv valve through its travel.
http://www.tvmadeez.com/index.php for some more tv info.

 

Anything '83-'87 that had a 350 in it and was prior to TBI injection. Trucks/Suburbans, Vans, Caprice/Impala are the best stock sources for Q-jet/700R4 pieces.

 

Weren't all U.S. GM cars, computer controlled carb, 81 and newer?

 

Why strange?

For several years from the mid-1960's through the 1970's, Carter and Rochester shared ideas and business. What a novel idea And it worked to the benefit of both companies!

Rochester came up with the spread-bore in 1965. Carter built millions of Q-Jets under license from GM for GM. These were 750 CFM (150 fixed, 600 variable).

In 1969, Carter, having all this Q-Jet experience, produced the "perfect" Q-Jet" (Carter called it a thermoquad, with all of the good features of the Q-Jet, and fixing the problems).

This initial production of TQ's were 850 and 1000 CFM. (250/600 and 350/650

The larger primary proved to provide a better transition in driveability from primary to secondary.

Rochester experimented with a 800 in 1970, and an 850 in 1971 (Q-Jets).

When Carter put the TQ in street production in 1971, the carbs were 800's (200/600) (for the smaller Mopar V-8's).

And when Chrysler started using the TQ on the 440's, they used an 850 (250/600).

Rochester learned from the 800 on the smaller engine, and in 1976 (I think this is the correct year, newer than my expertise) Rochester switched to all 800's for better transition.

Consider the history of the four barrel carb. The Chevy 265's used a Carter WCFB that was about 400 CFM (200/200), and it worked.

Jon.

 

Jon,
I was just alluding to the fact that even passenger 305's that year were 750's.
Of course, the C10 4.3 and the Astro vans were trucks, so that could have been the difference.

Just about the only thing that didn't switch over to 1.21 primaries from 1.09's were the SBC 's in passenger cars.
301 turbo cars, 252 Buicks, 4.3 Chevy were all 800's. This, according to NHRA Stock specs anyway.

 

I took three pictures of the numbers on the carb with my phone and you can't read the numbers. I will get you a pic with a real camera if that will help.

 

My 48 Chevy has an 85 Chevy 350 truck engine with a Q-Jet, 91 Camaro 700R4 and all I did was drill another hole in carb linkage to get the proper travel for the cable. I've got over 50k miles on it.

 

Good post. I actually saw that purple sage link, to me, it was easier to find the correct throttle shaft, which I did today.

Thanks for posting the link to that Street Demon carb. Didn't know those existed. If I'm not happy with the Q-Jet that would be the next carb in line for me to get.

The valve body is a neat item, however it's $pendy.

 

The 1988 (and possibly 1989) "Police" Chevy Caprice came with 350/700R4 with Q-jet. The intake manifolds were for center bolt heads and Q-Jet..I have a couple of those intakes.

 

Ok, re-did the picture in my old post and I think you can read the carb number now. Hope this helps.

 

Thank you.

 

All of the Chevrolet police cars had a 350 and 700 trans from at least 84 up to when they went throttle body.

 

TH350 cable is just a down shift cable. TH700r4 is a pressure regulator that has a different linkage for the carb to supply correct pressure through the throttle range. They sell correctors for the different carbs. If you don't use it, the trans self destructs on short order. All Holley Street Demons have the correct geometry for the 700r4.