The 1970-1971 Oldsmobile Cutlass SX Described

This 1971 SX convertible is even more laid back.

by Kurt Shubert, Olds Brand Manager

We all know that 1970 was considered to be the pinnacle year for performance cars and Oldsmobile approached the model year with guns loaded. A little known Factory inside publication called The Complete Automotive Performance Car ‘Scene’ was presented to Oldsmobile Zone Personnel in April, 1969. It gives insight as to what Oldsmobile’s plans were going into the ’70 model year. They outlined what the performance car market was by using what were then the common categories: “Supercars”, “Junior Supercars”, and “Sporty Cars”. They gave relative market share figures to fill in the picture. (You can read this entire report by clicking here).

Then Oldsmobile management explained where their cars fit in these categories. Their conclusion was: “Our strongest engineering objective since the introduction of the 442 back in 1964 has been to design balance – overall balance – into our performance offering”. They go on to say, “Performance cars are compromises, various aspects of vehicle design are often compromised for performance features. Oldsmobile, however, is not willing to sacrifice or compromise our product for the sake of performance parameters alone.” Translation; Olds performance cars would handle exceptionally well, not have a bone-jarring ride, and still perform.

As such, Olds offered as large span of performance cars, covering the Cutlass, 442, 88 and Toronado, most having a “W” series performance engine. For 1970, Olds had the W-31 Cutlass and W45 Rallye 350, the W-30 and 442, the W32 SX, the W33 Delta, and the W34 Toronado GT in their “performance car” arena.

Hidden in that mix was the Cutlass Supreme SX – a Cutlass Supreme Coupe/Convertible with option (Y79). The SX started the 1970 year as the newest version of the ’67 Turnpike Cruiser and the “economy” 442 of 1968-69. This new option gave one the L33 455 cubic inch big block with dual exhausts for torque, a 2-bbl carb and highway gears for economy, and an automatic trans for smoothness- stuffed in the new for 1970 Cutlass Supreme Coupe. It was a bit of a gimmick, because aside from the L33 engine and the P01 wheel covers that could otherwise be had on the Supreme, 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.

What we should also mention is that the Y79 option was available on both the Supreme hardtop and convertible, but not on the Cutlass S, the Cutlass Supreme 4-door, or the station wagon, all of which could receive a 455, but not the W-32 or the other Y79 specific treatments.

You could check off a few options like a console (the Supreme had buckets standard), sport wheel, Rocket Rally Pac, and the famed FE2 442 Rally Sports Suspension. That was pretty much it to start the year. The car would not have been very remarkable if the offerings stopped there. But they didn’t. During the course of the year, Oldsmobile Bulletins flew out of Lansing on a regular basis changing what was available on an SX. Enough to make a Salesman’s head spin.

What emerged was the W32, finally giving the SX its W-Machine status. Still a sub-option of the SX, the W32 engine was, however, one and the same as the auto trans 442 motor.  It also included the OG performance callibration to the mandatory M40 auto transmission.

So you could now start with a Cutlass Supreme, check off Y79, W32, and FE2 and voila! You have all of the performance features of 442! And by coincidence, I’m *sure*, you also have what was called a high insurance rate dodge, a big issue by that year.

What wasn’t available on your SX? Here are some of the key items:

• G88 3.91 Gears
• G91 3.42 Gears (W-32 only)
• M20 or M21 4-speed trans
• W-25 Forced Air Induction
• W-30 Package
• Y73 Hood Stripe

Here were the major changes to the SX during the 1970 year:

• Sept 5, ’69 Bulletin introduces the W32. It also announced the availability of the famed W27 Aluminum Rear Axle Carrier and Cover with the W32. Production records show that no W27 rears made it into Cutlass Supremes, so obviously no SXs had it.(To see and download this factory bulletin, click here).
• Feb 24, the L33 2-bbl 455 was dropped in favor of the L31 4-bbl 455. Not to be confused with the W32, the L31 was the basic 88-98 4-barrel 455. (To see and download this factory bulletin, click here).

1971 concluded the 2-year run for the SX, and for that year, it was pretty straightforward. It was basically the same as the ’70, but with only one engine for the whole year, the L32 4-bbl 455, now with lower compression and its net horsepower rated at 250. This engine was only available in the SX and the Vista-Cruiser wagon, and was also the only way to get a 455 in a Cutlass Supreme Coupe in 1971.

SX Production:

• 1970: 7122 were produced through June, so earlier reports of 7197 for the year are probably correct. ’70 W32: 852 were produced through June, so there were approx 890 for the year. That is a bit less than the widely believed 1025. As such, the W32 SX may be one of the rarest Olds muscle cars.
• 1971: SX production totaled 2177.

Muscle Car? Yes, Obscure? For sure.