Quadrajet Spec Guide available?

[G B.]

I've got a great Holley parts and specification book that Holley printed during the eighties. It allows me to check a "swap meet special" Holley carburetor by its List number to see if it has all its original matched parts such as the metering blocks, jets, power valve, secondary spring, etc.

I need access to a similar manual for Rochester Quadrajets now. I've got a couple of sixties carburetors that I think have been assembled from mis-matched parts. Even the baseplates are suspect.

It will take days of trial and error tests to get these Quadrajets sorted out if I don't start with matched parts. Does anyone have any Rochester or GM literature that would tell me which baseplates, jets, rods, hangers, etc. go with which Q-jet part numbers? The aftermarket manuals that I have for Q-jets lack this level of detail.

[Clem Z.]

Re: Quadrajet Spec Guide available?

i have the GM rochester service book that gives all the specs,but it gives GM part #s for the base plates,etc. it does give all the specs for jets,rods and other parts. i received this book years ago while going to GM carb school so they were not sold. i kept getting updates till GM quit using carbs.

[Clem Z.]

Re: Quadrajet Spec Guide available?

i have the GM rochester service book that gives all the specs,but it gives GM part #s for the base plates,etc. it does give all the specs for jets,rods and other parts. i received this book years ago while going to GM carb school so they were not sold. i kept getting updates till GM quit using carbs.

[G B.]

You're a lifesaver.

Clem -

Thanks so much for your quick response.

I'm trying to fix two 1970 454 Q-jets. One is stamped 7040204 FF 2769. Its baseplate is stamped 40687. The baseplate idle by-pass holes are open.

The other carb is stamped 7040205 EH 1420. Its baseplate is stamped 40688, and the idle by-pass holes are plugged (looks factory).

I'd like to know the original part numbers for the primary jets/rods, secondary hangers/rods, and if these two baseplates are the right ones.

I'm concerned because neither carb will idle with the open idle by-pass baseplate. Both carbs require so much primary butterfly opening at idle that the idle transition slots are fully exposed to intake vacuum. This richens the idle mix so much that you can screw in the mixture screws all the way and the engine won't die. Obviously something is wrong, but I can't do anything (other than experiment) until I know exactly what I'm working with.

[G B.]

You're a lifesaver.

Clem -

Thanks so much for your quick response.

I'm trying to fix two 1970 454 Q-jets. One is stamped 7040204 FF 2769. Its baseplate is stamped 40687. The baseplate idle by-pass holes are open.

The other carb is stamped 7040205 EH 1420. Its baseplate is stamped 40688, and the idle by-pass holes are plugged (looks factory).

I'd like to know the original part numbers for the primary jets/rods, secondary hangers/rods, and if these two baseplates are the right ones.

I'm concerned because neither carb will idle with the open idle by-pass baseplate. Both carbs require so much primary butterfly opening at idle that the idle transition slots are fully exposed to intake vacuum. This richens the idle mix so much that you can screw in the mixture screws all the way and the engine won't die. Obviously something is wrong, but I can't do anything (other than experiment) until I know exactly what I'm working with.

[Erv Schlepp]

Re: Quadrajet Spec Guide available?

Clem:

Does this book provide jetting sizes for a Q-Jet used on 1970 454 4 speed non calif. emmissions carbs. I would like to richen the fuel mixture but am not sure of the various size jets available

[Erv Schlepp]

Re: Quadrajet Spec Guide available?

Clem:

Does this book provide jetting sizes for a Q-Jet used on 1970 454 4 speed non calif. emmissions carbs. I would like to richen the fuel mixture but am not sure of the various size jets available

[Clem Z.]

Re: Quadrajet Spec Guide available?

i will need the number from the drivers side of the carb. starts with 170

[Clem Z.]

Re: Quadrajet Spec Guide available?

i will need the number from the drivers side of the carb. starts with 170

[Clem Z.]

Re: You're a lifesaver.

both carbs are for the same cars, 1970 396,402,454 all chevys, 204 auto trans, 205 manual trans, pri jets 78, pri rods 49, secondary rod 7033549, stamped AX, .040 dia tip. now comes the hard part as i only have the GM part #s for the throttle plates, 204,7041303, 205,7036812. there is no correlation between the #s you have and the part# so that is not much help.

[Clem Z.]

Re: You're a lifesaver.

both carbs are for the same cars, 1970 396,402,454 all chevys, 204 auto trans, 205 manual trans, pri jets 78, pri rods 49, secondary rod 7033549, stamped AX, .040 dia tip. now comes the hard part as i only have the GM part #s for the throttle plates, 204,7041303, 205,7036812. there is no correlation between the #s you have and the part# so that is not much help.

[Clem Z.]

PS

are you sure that you have the correct gaskets in the carb. lots of kits come with gaskets for different model carbs

[Clem Z.]

PS

are you sure that you have the correct gaskets in the carb. lots of kits come with gaskets for different model carbs

[G B.]

Thanks, and...

How about the secondary rod hangers?

One carb has an H and the other a K. I know they're close, but if the book says only one is right, I'll change the other.

[G B.]

Thanks, and...

How about the secondary rod hangers?

One carb has an H and the other a K. I know they're close, but if the book says only one is right, I'll change the other.