[Dick Boneske]

The '66 A.I.R. Tripowers used a different float bowl for the center carb than the normal Tripower cars. The "normal" float bowl was casting number 7031575.

The A.I.R. cars used ported vacuum for the distributor advance, which is not available with the 7031575 float bowl. The '66 Oldsmobile Tripower setups used a float bowl that was machined for a ported vacuum connection, also. The Olds and Pontiac A.I.R. center carb float bowls were likely the same.

I thought I knew the correct float bowl number for the A.I.R. setup, but now I'm not sure. Was it 7036175? I believe the only difference was the machining for the ported vacuum connection.

[Old Man Taylor]

Where is the casting number for the float bowl? It will be awhile before I want to remove or disassemble the carb if that is required to see the number.

[Dick Boneske]

Jim,

The casting number is located just behind & below the accelerator pump lever. You can see the location in the picture attached.

I didn't know you had a '66 Tripower setup--A.I.R.?

[Old Man Taylor]

I will have the car out tomorrow, I will check it then.

[Old Man Taylor]

Originally Posted by Dick Boneske

Jim,

The casting number is located just behind & below the accelerator pump lever. You can see the location in the picture attached.

I didn't know you had a '66 Tripower setup--A.I.R.?

I'm guessing it came off of an A.IR. car. It's a California smog carburetor. It has the ported vacuum port and the hot idle compensator (which I took off).

[Dick Boneske]

Thanks. We'll see if the correct casting number is 7034175.

[Old Man Taylor]

I didn't have enough hands to get a clear picture, but the P/N looks like 7031624.

[Dick Boneske]

Thanks, Jim, for the feedback. It does look like 7031624. If you know the history of your Tripower, the casting number is likely the correct one.

John Hardgrove's Tripower spec summary says it should be 7036175. From info I have, I thought the float bowl should be 7031674. I have two unknown float bowls casting numbers 7031764 and 7031794. I can't find a reference list other than John Hardgrove's.

I know for sure the standard '66 center carb float bowl is casting #7031575.

In any case, I'm trying to restore a A.I.R. setup for someone and found his center carb float bowl to be unusable as he sent it to me. The accelerator pump bore is badly corroded. Sleeving is not feasible due to the thin casting walls. I don't have confidence that JB Weld would hold up in that application--even though I've done many repairs that are exposed to fuel with 100% success. The pump bore is exposed to mechanical friction as well as fuel, which is why I don't want to try it. I'm waiting for a local machine shop to bore the pump well to remove the crevices caused by corrosion. There is a carb application that uses a pump cup 1/16" larger than the 3/4" ones used on standard '66 Tripower carbs. That may be the final solution for this carb.

If anyone else has info on the float bowl casting number for A.I.R., i'd appreciate your sharing it. I'm not confident the bowl I have is the correct A.I.R. piece, especially after Jim Taylor gave me the number off his.

[Dick Boneske]

Finally got the carb back from machining the pump bore. Needed a 1/16" overbore to clean up the pump well.bore. Actually, the front carb and the center carb had this pitting problem so we bored them both. A 13/16" pump cup instead of the stock 3/4" cup fits perfectly, so we saved the carbs.

This post is to let you know, Jim Taylor, that you were correct. The center carb float bowl for a '66 A.I.R. setup is casting # 7031624.

Chalk up another win for OMT!!.

Thank you.

[Dick Boneske]

I used the Carter accelerator pump cups that measure 13/16" vs. the standard bore of 3/4". This worked fine after the bores were enlarged by 1/16" to remove the severe corrosion/pitting on the front and center carbs.

If any of you find it necessary to do this on a large Rochester 2 bbl., be aware that the Carter pump cup has a 1/2" hole in the center vs. the 3/8" hole in the standard pump cup. If you put an "O" ring (Fluorelastomer so it's ethanol-proof) measuring 1/2" OD X 3/8" ID over the pump shaft, the pump cup stays centered and seals so it works properly.

Here are the carbs on a spare '66 manifold I have. It would have been a shame to discard the front and center carb (a rare one) instead of fixing the problem. Note how nicely the exterior of the carb bodies colored.

[carbking]

Originally Posted by Dick Boneske

Thanks, Jim, for the feedback. It does look like 7031624. If you know the history of your Tripower, the casting number is likely the correct one.

John Hardgrove's Tripower spec summary says it should be 7036175. From info I have, I thought the float bowl should be 7031674. I have two unknown float bowls casting numbers 7031764 and 7031794. I can't find a reference list other than John Hardgrove's.

I know for sure the standard '66 center carb float bowl is casting #7031575.

In any case, I'm trying to restore a A.I.R. setup for someone and found his center carb float bowl to be unusable as he sent it to me. The accelerator pump bore is badly corroded. Sleeving is not feasible due to the thin casting walls. I don't have confidence that JB Weld would hold up in that application--even though I've done many repairs that are exposed to fuel with 100% success. The pump bore is exposed to mechanical friction as well as fuel, which is why I don't want to try it. I'm waiting for a local machine shop to bore the pump well to remove the crevices caused by corrosion. There is a carb application that uses a pump cup 1/16" larger than the 3/4" ones used on standard '66 Tripower carbs. That may be the final solution for this carb.

If anyone else has info on the float bowl casting number for A.I.R., i'd appreciate your sharing it. I'm not confident the bowl I have is the correct A.I.R. piece, especially after Jim Taylor gave me the number off his.

Dick - the 7036175 listed on my website is the TAG NUMBER of the carburetor, not the bowl casting number.

I had no information on the bowl casting number for the California only center carb.

Rochester's numbered scheme goes awry in 1966. Rochester started with 700nnnn, then 701nnnn, then 702nnnn, then 703nnnn. In 1966, California smog was introduced, and Rochester started using the 703nnnn for carb numbers to denote California smog.

The non-smog bowl 7035(175) and the carb number 7036(175) are co-incidental. Note that since the 5 in the 7031575 denotes year (before smog emission), it could not be a carburetor tag or identification number.

I will update the listing to show the bowl casting number.

Jon.

[carbking]

Website now updated to show bowl casting number.

Thanks - Dick and OMT

Jon.

[Dick Boneske]

Thanks, Jon.

I should have noticed the number you posted was the tag number. After all that, we're now OK!

Dick

Originally Posted by carbking

Website now updated to show bowl casting number.

Thanks - Dick and OMT

Jon.

[60sstuff]

I bought this complete unit at a swap meet in 1979.

This is the setup that would have come on a 66 WV code GTO using that 7031624 center.

[Dick Boneske]

Thanks for posting. I wonder if Olds used that same center carb in '66 on their three carb setup. I know it used ported vacuum for the distributor.

[60sstuff]

Dick, Jon

All three aluminum tags.

Front - 7025178 (M4)
Center - 7036175 (M5)
Rear - 7025179 (M4)

Chris.

[topfuel67]

I'm glad I found this post! My 66 is a CA AIR tripower. I've been piecing together a tripower for her. One of the first carbs I acquired has the 7031624 fuel bowl. I didn't think it was a tripower carb, and used it as my first to learn how to clean and dichromate.
The airhorn doesn't have the idle vent valve. Is this correct?

[Tom Vaught]

No idle vent valve on California Carbs.
Evaporative emissions deal, same as the breathers on the valve cover connected to the tri-power bases.

Tom V.

[Dick Boneske]

The 7031624 I just restored did have an airhorn with the idle vent. I don't know if that was the original airhorn.

Makes sense that the CA units had no idle vent. I wonder if anyone ever considered that the float bowl vent at about 1/4" diameter allows much more evaporation than the idle vent.

[60sstuff]

Originally Posted by Tom Vaught

No idle vent valve on California Carbs.
Evaporative emissions deal, same as the breathers on the valve cover connected to the tri-power bases.

Tom V.

Tom V.

Every 66 A.I.R. Tri-Power I have seen has the “Idle Vent Valve”, including the unit I posted above.

Chris