[topfuel67]

I have found a 1966 Rochester Center Carb with the 7031575 fuel bowl and the 31892 base, but it doesn't have the airhorn with the vacuum choke. It has the choke on the base. Were these used on the GTOs or is this how they were for others brands like Olds? Or has it just been rebuilt Frankenstein style?

[Dick Boneske]

I believe the "575" float bowl is unique to the '66 GTO Tripower. There are other large 2G's that have similar airhorns with choke pulloff, idle vent.

You can use the base you have by plugging the holes where the choke bolts on and the vacuum hole. If you're careful, you can do this so it looks like the '66 Tripower base. They have the casting boss for the choke housing, but it's not machined.

If you want, I can give you some similar airhorn numbers.

[topfuel67]

Yes, please let me know other similar airhorn numbers are.
Thank you

[Dick Boneske]

The "575 float bowl has venturis sized at 1.190". There are several float bowls similar to the "575" that have larger venturis--they include casting numbers 7034764, 7032270, 7038001, 7037601. There is a 7031624 that has 1.190" venturis like the "575" does. These all look very similar to the "575" in every aspect, including the idle vent. Differences are in the backside where casting bosses differ. The most plentiful casting is the 7037601, which was used in the mid '60's on Firebirds and Tempest V8's with a single two barrel. Note that it has the larger venturi size. I believe the float bowl used on the '72 455 big Pontiac 2 bbl. engine has even larger venturis.

The "correct" '66 airhorn is casting #7031587. Another casting, 7035744 is identical in appearance except for the word "filter" cast on the fuel inlet boss. Another similar airhorn is the 7038585, but it has a cutout in the rear of the air cleaner boss that the original did not.

There are many more casting numbers besides the ones I've noted above for float bowls and airhorns that will work for Tripower applications. Mods to the venturi cluster will be necessary to accommodate hotter cams, big cubic inch engines.

[mike w]

The carb you pictured is off a 1966 Pontiac...not a GTO. The "575" casting number appeared on this carb as well as the correct 66 center carb.

The choke on your carb was mounted on the throttlebody. The GTO center carb had choke pull-off mounted on the airhorn.

Hope this helps.

Mike@pontiactripower