Geoff Coenen
Well-known member
I read this CF thread –
https://www.corvetteforum.com/forums/c3-tech-performance/4848086-tri-power-carb-base-gasket.html
A fellow from Germany with a C3 tripower is looking for a set of Kormetal style gaskets. Those were marketed by Holley, for 2 barrel Holley carbs – Holley part number 108-9 – used on Mopar, GTO and presumably Corvette, Note they are symmetrical on a vertical axis, while the GM blueprint for C3 tripower are asymmetrical. Another CF fellow states that the end gaskets have a larger bore diameter than the center gasket. Note that Holley only listed one gasket for all 3 positions – and since they were sold individually one can assume all 3 were the same.
After reading this thread I suspect some of the information is not accurate - so I looked at these in my own library of GM published material.
The 1938-1967 GM P&A 30 (Parts and Accessories) catalog published in 1966 shows GM part number 3902372. I do not have this GM blueprint – however P&A shows 3 being required - so theoretically they must all be the same – since there is only one part number for all 3 and they are not sold as set where one could be different from the others.
The 1967 AIM has the same GM part number listed for the carb to intake gaskets – GM 3972302. The blueprint revision notes it was replaced by GM 3921922 on Jan 24, 1967 or April 24, 1967 – the print if blurry – it is either 1-24-67 or 4-24-67.
The 1968 GM Part History Catalog shows the 1967 GM part number 3902372 was discontinued in August 1967 and replaced by GM part number 3921922. Apparently that 1967 part number was short lived.
The 1968 AIM as well as the 1969 AIM’s both show the GM 3921922 carb gasket part.
GM Blueprint part number 3921922 is dated January 30, 1967 – I have this genuine GM blueprint – sent to me by the GM director of Warehousing and Distribution in the late 1980’s – early 1990’s
This GM blueprint has no revisions listed in the revision box in the upper right corner and the AIM does not have a note that this GM part number was 3921922 changed from another in 1968 or 1969. The change over occurred around January to May 1967
On the blueprint both the ends and center gaskets are illustrated and the bore diameter is the same for the ends and the center - 1.81 inches in diameter. The only different between the 2 ends and the center is a message “to be roll stamped on Black backround with White ink or paint”. The left side illustration shows this message “THIS SIDE UP END CARBURETORS”. The right side illustration shows the center gasket flipped over with this message “THIS SIDE UP CENTER CARBURETOR”. The gaskets are the same and anyone with a 3x2 knows or should know these center gasket simply gets flipped over. So one side of the gasket was printed – this side up and the other side printed – this side down.
I do not know if the first design 1967 part number had a different bore diameter for the center carburetor – since I don’t have that blueprint – however I seriously doubt it. The second design 1967 thru 1969 blueprint shows both the 2 end and center carb gaskets have the same bore diameter. I took this jpeg and included my 19.95 Walmart flip phone showing the date Thursday July 25, 2024
I also have 2 new Holley spare end carburetors and 1 spare center in my home garage and I’m not going to measure their bores – nor am I going to measure them on my 1969 400/427. In the past 35+ years no one has ever said these interfered with the center carb butterfly valves.
Perhaps there were aftermarket versions that had different bore diameters – but the Holley Koremetal gasket does not provide 2 different different examples either.
Methinks this is just a boring old Corvette wives tale. But WTFDIK
Lastly Al Fierke – aka Chicago Corvette Supply formerly of the windy city – now transplanted on the left coast in Oregon or Washington state offer the 3 piece set below for Corvette. Hmmmmm ….
I’d love to get GM blueprint of the 3921922 for the first design Corvette 3x2 gasket – but I’ll not lose sleep over it.
https://www.corvetteforum.com/forums/c3-tech-performance/4848086-tri-power-carb-base-gasket.html
A fellow from Germany with a C3 tripower is looking for a set of Kormetal style gaskets. Those were marketed by Holley, for 2 barrel Holley carbs – Holley part number 108-9 – used on Mopar, GTO and presumably Corvette, Note they are symmetrical on a vertical axis, while the GM blueprint for C3 tripower are asymmetrical. Another CF fellow states that the end gaskets have a larger bore diameter than the center gasket. Note that Holley only listed one gasket for all 3 positions – and since they were sold individually one can assume all 3 were the same.
After reading this thread I suspect some of the information is not accurate - so I looked at these in my own library of GM published material.
The 1938-1967 GM P&A 30 (Parts and Accessories) catalog published in 1966 shows GM part number 3902372. I do not have this GM blueprint – however P&A shows 3 being required - so theoretically they must all be the same – since there is only one part number for all 3 and they are not sold as set where one could be different from the others.
The 1967 AIM has the same GM part number listed for the carb to intake gaskets – GM 3972302. The blueprint revision notes it was replaced by GM 3921922 on Jan 24, 1967 or April 24, 1967 – the print if blurry – it is either 1-24-67 or 4-24-67.
The 1968 GM Part History Catalog shows the 1967 GM part number 3902372 was discontinued in August 1967 and replaced by GM part number 3921922. Apparently that 1967 part number was short lived.
The 1968 AIM as well as the 1969 AIM’s both show the GM 3921922 carb gasket part.
GM Blueprint part number 3921922 is dated January 30, 1967 – I have this genuine GM blueprint – sent to me by the GM director of Warehousing and Distribution in the late 1980’s – early 1990’s
This GM blueprint has no revisions listed in the revision box in the upper right corner and the AIM does not have a note that this GM part number was 3921922 changed from another in 1968 or 1969. The change over occurred around January to May 1967
On the blueprint both the ends and center gaskets are illustrated and the bore diameter is the same for the ends and the center - 1.81 inches in diameter. The only different between the 2 ends and the center is a message “to be roll stamped on Black backround with White ink or paint”. The left side illustration shows this message “THIS SIDE UP END CARBURETORS”. The right side illustration shows the center gasket flipped over with this message “THIS SIDE UP CENTER CARBURETOR”. The gaskets are the same and anyone with a 3x2 knows or should know these center gasket simply gets flipped over. So one side of the gasket was printed – this side up and the other side printed – this side down.
I do not know if the first design 1967 part number had a different bore diameter for the center carburetor – since I don’t have that blueprint – however I seriously doubt it. The second design 1967 thru 1969 blueprint shows both the 2 end and center carb gaskets have the same bore diameter. I took this jpeg and included my 19.95 Walmart flip phone showing the date Thursday July 25, 2024
I also have 2 new Holley spare end carburetors and 1 spare center in my home garage and I’m not going to measure their bores – nor am I going to measure them on my 1969 400/427. In the past 35+ years no one has ever said these interfered with the center carb butterfly valves.
Perhaps there were aftermarket versions that had different bore diameters – but the Holley Koremetal gasket does not provide 2 different different examples either.
Methinks this is just a boring old Corvette wives tale. But WTFDIK
Lastly Al Fierke – aka Chicago Corvette Supply formerly of the windy city – now transplanted on the left coast in Oregon or Washington state offer the 3 piece set below for Corvette. Hmmmmm ….
I’d love to get GM blueprint of the 3921922 for the first design Corvette 3x2 gasket – but I’ll not lose sleep over it.
