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The official club for enthusiasts of the

1970 & 1971 Oldsmobile Cutlass Supreme SX


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Bob Peters
SX455 Club President
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General Cutlass SX455 Q&A

Looking for help validating an SX I my purchase
Author Last Post

You might try the GM Heritage Center, but I'm pretty sure there are no Olds invoices or build sheets available unless your car was built or sold in Canada.

The Canada site is

Gary Goodman
Hi Brian, do you have the number for GM vintage cars? I'm trying to find the build sheet for my SX Convertible.
Call gm vintage cars, give them the serial number, if they find any info they will fax it to u, I think mine cost $75. If they cant find any info then the still bill you $35.
Not all SX's had body side mouldings. My 71 did not have it. And it is
a GM documented SX
Good thing that it is built in Linden NJ. It should have 1 or 2 build sheets if they weren't remove at an earlier date. Hope you are able to get it and post more pictures when you can.
Oh, and the OAI hood is metal, not fiberglass and is functional. That's a big bonus.
Thanks Mike. Car does have notched rear bumper. I know the side moulding is missing but I think it looks better without it anyway. I am going to look at it again tommorow to see about matching numbers engine and tranny. Was dressed too nice last time I was there to crawl under the car. Hoping it all matches.
Hi Ed,

Good looking car.

- Does it have a notched rear bumper with dual exhaust?
- You'll want to check the VIN derivative stamped on the engine block pad below the #1 spark plug. The last 6 digits should match the last 6 digits of the VIN.
- Validate the same VIN derivative on the transmission. The numbers can be found on the drivers side.
- Incidentally, the SX should have lower body Supreme molding.
- The OAI hood is a bonus if factory or Thorton's repop

Hope this adds some insight.

I joined because I have found what I believe to be a 1970 SX convertible that I am interested in buying. I have owned 3 Cutlasses in the past (all hardtops with 350 engines) - a 1971 Cutlass, a 1970 Cutlass post car, and a 1971 Cutlass S. For the last 6 months I have been looking for a 1970 or ’71 442, but during that time discovered the story of the SX and all its glory. I came across one a few weeks ago and am trying to figure out if it is real.

Here’s what I do know –
The current owner bought in back in April of this year as a backup to his AC Cobra kit car when he needs more room or the weather is tempermental. He is looking to sell it because he doesn’t have the room to store it for the winter. He tells me he bought it from an older gentleman who told him he just didn’t use it much and wanted the money to buy a boat (he lives by the ocean). Neither of these gentlemen have the Build Sheet or Invoice, but neither have looked in the car for the Build Sheet which means it could still be there. I have inspected the car as well as driven it, and this car moves (0-70 in no time at all)! Nothing tells me it is not an true SX based on my research, but I’m no expert. However based on all my research on line, this group appears to be the ultimate SX experts. So I'm looking for some help please.

The VIN is 342670E175135. It has a 455 with Quadrajet 4 bbl, TH400, Bucket seats with stock floor shifter (not his/hers), correct emblems on the fenders with proper placement, A/C, power windows and door locks, tilt sport steering wheel, non-posi rear end with what we believe is 3.08 or 3.23 gears. Motor was painted gold but current owner because he thought all Olds motors were gold. I informed him only 350’s were gold, 455’s were blue. Body tag tells me car was built in Linden, NJ on the last week in April or 1970, original paint color was Aspen Green, and it came with black bucket seats. I have attached some photos. Be curious to hear your thoughts. Appreciate any insight you may have.

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