Hi. This is Bob. I've done some research and believe my 70 cutlass convertible has its original 455 and is not a 442. the trans is auto with column shift, but the speedo has no shift indicator. the vin starts with 342670E. There is an ancient decal on top of the radiator bracket that spec's the 455. But I have found no prod nums for convertible 455 cutlasses.

my question is, is this rare, and if so what might be a value range? I would not want to over-restore it. it runs clean, has a new functional top, little rust, but needs a lot of paint and upholstery work.

Any guidance will be much appreciated.

 

I don't think a breakdown of Cutlass production by engine type is available for this era of Oldsmobiles. Someone will certainly correct me if I'm wrong. The base engine for your car was the 350 V8 with the 455 as an option. While there were likely more 350's than 455's in '70 Cutlasses, I would guess that the fraction that were ordered with a 455 was not small.

We can tell you that your car is a Cutlass Supreme as the Supreme was the only version of the Cutlass available as a convertible that year.

The VIN doesn't tell you more than you already know. It decodes as a 1970 Cutlass Supreme convertible built at Linden, New Jersey. The 442 was a separate series in 1970, so the VIN would indicate a 442 if that's what the car really was. So yours is not, as you thought.

Production of '70 Cutlass Supreme convertibles was 11,354. How rare are they? How rare is any car from back then? There is no way to determine exactly how many are still on the road today as no one maintains a database like this.

Historic vehicle scrappage rates, which are available on government websites, show that a very average number is 1% of a vehicle's production is still on the road 25 years later. That would suggest that maybe 100-150 of cars like yours are still around. The figure is probably higher as people tended to keep convertibles more than sedans. Maybe 200? Maybe 300?

 

As far as value for your car, the Old Cars Price Guide, June 2012 issue, lists the value of a 1970 Cutlass Supreme convertible in #3 condition ("car show" condition but not showroom condition) at just over $11,000. In showroom condition (#2), the value given is $17,500. If it's just a driver and needs complete restoration (#4 condition), the value is $5,000. Of course, you add and subtract at any of these levels based on the particulars of the car in question.

 

If it is an original 455 for your car, it will have E heads. Look on the side/front of the drivers head & you should see a letter about 1" high. just below that on the block you will find a small flat pad about 2-3" long & about 1/2 " high. There are some numbers & letters stamped there. The last 6 numbers will match you vin if it is the original engine. It might be hard to see these numbers/letters & you might need to take a wire brush to this area. A mirror & flash light might help also. Maybe take some pictures of the engine bay & interior & we can answer more questions. Also, if it is a factory 455 in your car, the washer jar should be on the passenger side inner fender. The 455 cars had a larger battery & battery tray & that necessitated the jar to be moved from the drivers side to the passenger side.

 

Can you take a picture of the cowl tag, or tell us the build month and week?
Can you look for the transmission code tag, which is on the passenger side just above the oil pan, just next to where the vacuum line goes. Give us the information on the tag or a picture.
Also, on the driver side of the transmission, just near where the shift lever is there will be a small flat area with what looks like the VIN. Does that match the number you found on the engine, and the car VIN.
Does the car have dual exhaust? If so, does it have cutouts in the bumpers for the exhaust tips?
Does it have the boxed in lower rear control arms?
Does it have a rear sway bar?
Can you find the axle code, usually on the passenger side axle, facing forward: this will be two characters, for example R2 or R3 or SC.
Can you find the part numbers and date codes on the distributor and the carb?
Does the car have front disk brakes?
None of these will definitely and uniquely identify the car, but will help form an idea.
Here is the holy grail - can you find the build sheet? The easiest place to look is up under the front seat, between the coils and the stuffing. Linden built cars often have a build sheet. It could be under the rear seat, harder to find, or on top of the gas tank, hardest to find.
As to the value of doing a full restore - who knows. I would say that you would never get your money out of a full blown restoration unless you do all the work yourself for $1 an hour. You do it because you want to.