Considering a 71 SX Convertible. What should I be looking for to assure its authenticity? Thanks.

 

Unless the seller has some kind of factory paper work that states SX on it somewhere, there is no 100% positive way to prove it is an SX, as far as I know. You can look for several clues on & in the car but all of that could be added by a previous owner. Check to see if the last six numbers of the VIN match the 455 block. Unless engine has been changed at some point.

 

It should have the boxed in lower rear trailing arms. Heavy duty front sway bar and rear Sway bar. Double check the numbers on the vin and the engine block. Make sure they are the same. Check all of the options. Options add value. Electric windows, Tilt steering wheel, Rally pack gauges, his/her shifter and posi trak. Again, SX cars didn't always come with these options but they do add value.
Don't pay for an SX unless you can absolutely confirm it is an SX. So many cars a cloned and some clones are very well done. But they're still clones.
Good Luck

 

So you are saying that the FE2 suspension package was mandatory on the SX? Are you sure?

 

I am definitely not an expert.
So I did some research.
The only thing specific to the SX was the emblem package, a notched rear bumper and exhaust trumpets from the 442, and the code OD mandatory M40 automatic trans.
The FE2 suspension is just an option.
Good catch

 

I could be wrong but wasn't the OD code TH400 only found in the SX in 71?

 

Yes you are correct. Also I believe the extra braces running from the front of the lower rear control arms up to the upper rears are on big block convertibles as well as big block hardtops. Convertibles did not receive the front fender big block braces that are found on the SX and 442 Hardtops in 70 and 71. Most people cloning, wouldn't know about the braces and most would clone to a 442 as it is worth more.
If the 455 VIN and TH400 VIN matches the body VIN you would be as sure as is possible without documentation

 

The OD TH400 was used on all SXes in 1971 since they were all L-31s.The OG was used on the W-32 SXes in 1970; the L-31 and L-33 SXes used the OD.

The SX badge should be offset with the left edge starting under the 'ss' on the fender Cutlass emblems. If they are centered or positioned any other way (I've seen bad ones), they're wrong and maybe a sign of a bad clone.

I managed the sx455.com MIA cars section for years (and still have an interest in it). I found at least three documented #s matching 455 1970 Supreme hardtops (all L-33 2-barrels) that were not Y-79 SX cars, so they are out there. Can't say that I've seen the same for a 1971 yet.

Having a broadcast card, build sheet or original window sticker with a Y-79 on it is your best bet for authenticating one. Better yet, PM me with a VIN and/or pics and we'll see if its in the sx455.com registry or my personal 20 year stash of pics and ad screenshots.

Terry

 

In 71 the 455 was only available in the Cutlass Supreme series with the Y 79 option (SX).

Don W

 

Thanks for the info. about the trans. Always good to learn more.

 

Great info help here guys.
I've been looking for a replacement Cutlass for the one I sold years ago to pay for getting married.
Mine was a 1972 Supreme. Loved the car.
Now looking at a 1971 SX. Interesting history on the SX.
Low production numbers, big block, convertible, low mileage, high optioned car.
What would you think I should offer for it with the idea that I am going to keep it and not just buy to flip it?
Assuming it is a true SX car.
Thanks for any input.

 

So if the Y79 = SX. Does that mean any 1971 Cutlass Supreme with matching numbers 455 is a documented SX? What about 1970, could you get a Cutlass Supreme with a 455 without it being an SX?

 

I thought you could...my proof..a little birdie told me..
Somebody called my Supreme a SX clone...I guess it is..lol

 

Yes, at least with the L-33 2 barrel in 1970. I have found three hardtop Supremes with full build sheets that were not Y-79 cars over the past decade while capturing info for sx455.com.

 

Cool..

 

The L33 2bbl was dropped early in 1970. There was a bulletin issued indicating the change in engine offerings. After the changes the only way to get a 455 in a Cutlass was by option Y79, (SX) and only in a Cutlass Supreme coupe and convertible. The choices were then the regular 455 4bbl. with the OD transmission or the W32 which was a 442 455 with the OG TH400.
In 71, it was much simpler, one 455 L32 and the OD TH400. 1820 Hardtops and 357 convertibles were built.

 

Here is an interesting tidbit for the 70 model. This was from the 70 beater
I had a few years ago. I don't remember much about it other than it was a 455 2 bbl, E head, a/c, bucket, console Supreme with the OD transmission. I never pulled the tank to look for the build sheet, but found the broadcast card under the carpet.

I have no idea who's or where that 70 Supreme came from on the next photo.
Ted, is that yours? Well, by golly it is!

 

My 1st Oldsmobile was a 1970 Cutlass Supreme L-33 455 2bbl non SX car. I sold the car when I bought my second Oldsmobile (my 1972 W-30). The new owner of the Cutlass Supreme promptly turned it into an SX clone.


There has been some discussion on this board of these cars. Joe has posted production numbers for them.

 

Buddy had a 72 CS in 1988 with every option the planet... FE2, 455, power everything... power bench, tow pkg, air lifts etc. It was a 4 bbl car and I think it had Rallye dash too. Ill have to ask him to see if he remembers that detail. It was just a loaded to the gills 72 CS. Interesting car.

 

I am pointing this out just as a why even mention this car.There were no 1972 sx cars. This thread is about a 1971 sx. 1970 and 1971 was the only years. I am not trying to offend anyone here just pointing out facts.

 

Oldsmobile opened the floodgates in 72 with regard to the 455 option. You could order a 455 in any A-body in 72, negating the need for the SX option. A plain Jane F85 four door sedan could have a 455 if one desired. Perhaps they wanted simplify things being the last year of that body or had an abundance of certain parts to use up. It would be interesting to know how many F85 455s were produced. Trailer towing would be my guess for buying one.

 

Although I have seen many 1972 U code Vista Cruisers I can only recall ever seeing one U code 4 door Cutlass for sale.

 

I have a 1972 U code 4 door hardtop sedan. No frames around the door glass. It had many options when I got it but was pretty far rusted. I still have the carcass and am using it as storage.

 

I just was going to mention that car Scott!

 

Hey were not supposed to talk about 72s you guys.

 

So what are the SX cars worth these days?
Lower end...$20k upper end $35k ?
Thanks