66 Toronado Carb ID - Help!

[ourkid2000]

Good day all,

I have a couple Quadrajets that came with my 1966 Olds Toronado and I've been trying to identify at least one of them since I got it. So far I have been unable to tell which one is the "original", although I have my suspicions.

My dad bought this Toronado back in 1973 from the original owner and we have all the paperwork and service records but almost nothing on the carbs. Since then, he's pretty much babied this car but he ended up getting a replacement Quadrajet from a family member in the USA to try to solve the "original" QJ's leaking fuel inlet (we are in Canada). Unfortunately, the paper trail on that replacement carb wasn't great and now we don't know which is which.

So, here I am taking over on this car and I'm trying to play detective. I have my suspicions that the carb currently installed on the car is the original. This is an AIR car so it should have a bit of an oddball Qjet on it (should be PN 7036250). Once again, our luck isn't good with this because on the side of the carb where the PN should be (in the round depression) the little circular tag has fallen out.

The carb I'm suspecting is the original seems to check all the boxes. It has the round depression on the side for the PN tag, the choke assembly looks right, and it's got the external vent on the front.

The other carb we have has no round depression on the side for the PN tag, however it also has no PN stamped vertically on the body as you would expect. The external vent on the front has been plugged as has the hot ilde compensator thing at the back. Both carbs have the 1966 hallmark.......secondary dashpot linkage.

I guess the only thing we don't know is weather or not from 1966-1973, was the original carburetor replaced? My family member, who got this carb for us back in 1988 wrote a note, which I still have, saying that the carb shop he got it from said that all the parts on our existing carb could be swapped on to this carb to make it correct. Who knows right?

So I just went down to the garage and inspected the carb for PN's. I have noted the following PN's:

Air Horn : 7031110
Float Bowl: 7032720
Base plate: 7032502

I grabbed my 1972 parts catalog, went to the 1966 4MV section and the Service Carb section and none of these PN's are shown as valid.

I've attached pictures of the carb I'm suspecting came with the car, but again I'm not sure. Maybe someone here would know? I hope all this makes sense. Any questions just let me know!

[ourkid2000]

TLDR:

Two owner 1966 Olds Toronado. My dad was 2nd owner, bought in 1973.

- I have 2 QJ's and am unable to tell which one is which as carb PN's not on bodies.
- Unsure if I even have the original 7036250 as it may have been replaced prior to 1973 (just a guess)
- Rochester QJ component part # stamps provided with pictures. These are on the installed carb which is the one I suspect came with the car in 1973.
- Second carb was obtained back in 1988 from California. Supposedly, parts could be swapped to that carb to make it work on the Toronado.

[Cliff Ruggles]

"The other carb we have has no round depression on the side for the PN tag, however it also has no PN stamped vertically on the body as you would expect. The external vent on the front has been plugged as has the hot ilde compensator thing at the back. Both carbs have the 1966 hallmark.......secondary dashpot linkage."

Missing a place to install the round tag is your first clue that this isn't the original carb. 

Plugged idle vent and HIC another clue that it's probably some sort of commercially "remanufactured" carb built to replace the original.

I suspect that the carb in the pics is the original carb......

[ourkid2000]

Ok, that's good info. So, I'm curious....if we assume that we have identified the original carb, why don't the part numbers on the carb match what is in the parts catalog?

Physically on the carb:
Air Horn : 7031110
Float Bowl: 7032720
Base plate: 7032502

Note that since 1973, this carb has been on the car. If anything had happened to it, it must have occurred prior to 1973.

See attached parts catalog pics:
Air Horn: shows No Longer Available, so not much help there
Float bowl: should be 7033009
Base plate: should be 7031117

[Shiny]

I'm following with interest.

I too have a carb with throttle body and airhorn numbers cast into them that don't match the Delco PN listings for the Bowl - same as you are sharing.  They also have stamped numbers but I have not found a "decoder" listing similar to the Delco docs.  In my case, I don't know the carb's history but I'd like to avoid dealing with mismatched carb parts if I choose to rebuild it.

[Kenth]

Info from Jon Hardgrove @ thecarburetorshop:

Casting (raised) numbers: Raised numbers appearing on various castings are so-called "casting" numbers. These numbers were used by Rochester to identify a casting "blank" PRIOR to machining. A casting could be machined into different parts. IT IS IMPOSSIBLE TO IDENTIFY ROCHESTER CARBURETORS FROM CASTING NUMBERS ALONE!

Unfortunately this is true.

And, part numbers in the Delco manual are spare part numbers on assembled units with parts attached. Not only the separate air horn, float bowl or throttle plate.

HTH

[ourkid2000]

Info from Jon Hardgrove @ thecarburetorshop:

Casting (raised) numbers: Raised numbers appearing on various castings are so-called "casting" numbers. These numbers were used by Rochester to identify a casting "blank" PRIOR to machining. A casting could be machined into different parts. IT IS IMPOSSIBLE TO IDENTIFY ROCHESTER CARBURETORS FROM CASTING NUMBERS ALONE!

Unfortunately this is true.

And, part numbers in the Delco manual are spare part numbers on assembled units with parts attached. Not only the separate air horn, float bowl or throttle plate.

HTH

Okay......that makes absolutely no sense. How do they determine what parts they have when they're manufacturing the carbs??

[Kenth]

It is a production technical question that can only be answered by Rochester.
But I'm sure they had a system that worked as they were able to produce more than 15000 one, two and four barrel carbs daily.

[ourkid2000]

I'd love to have that picture on my wall......great snap!

[Shiny]

Info from Jon Hardgrove @ thecarburetorshop:

Casting (raised) numbers: Raised numbers appearing on various castings are so-called "casting" numbers. These numbers were used by Rochester to identify a casting "blank" PRIOR to machining. A casting could be machined into different parts. IT IS IMPOSSIBLE TO IDENTIFY ROCHESTER CARBURETORS FROM CASTING NUMBERS ALONE!

Unfortunately this is true.

And, part numbers in the Delco manual are spare part numbers on assembled units with parts attached. Not only the separate air horn, float bowl or throttle plate.

HTH

This makes sense to me.  When chasing my Frankencarb I was told differently and it added confusion.

I expect a single casting was "customized" for multiple applications.  Once assembled, the physical tracking would have to be stamped or otherwise tagged if it was intended to be "traceable".  The castings are indeed stamped, which to me is the likely "sub-assembly" number.  For example, I expect the same airhorn casting could have different nozzles or DCRs installed, then stamped to differentiate.

But I never found a source for decoding the stamped numbers...

Kenth - do you catalog these stamping numbers?  Is there any pattern to them?

[Shiny]

I'd love to have that picture on my wall......great snap!

Agree!

In one previous life I developed manufacturing processes for electronics so that photo is a blast from my past.

Thanks for posting that, Kenth.