With 400 horsepower and 500 lb-ft of torque, the big Toronado GT was the most powerful machine in the Oldsmobile lineup for 1970.

As the muscle car trend was peaking in the late ’60s, the Motor City’s automakers decided there was a market for senior muscle cars, if you will: roomy, luxurious full-size cars combined with muscle car-style powertrains. Chrysler’s entries included the Plymouth Fury GT and Chrysler 300H, while Mercury offered the Marauder X-100 (see our feature here). For 1970, Oldsmobile slipped into the category with the one-year-only Toronado GT. With 455 cubic inches, 400 horsepower at 4,800 rpm, and 500 lb-ft of torque at 3,2000 rpm, it was the most powerful Oldsmobile in 1970—in its advertised output rating, anyway.

Actually, the 400-hp W34 engine was offered in the front wheel-drive Toronado in ’68 and ’69, and in its first year it included a cold-air intake package (“Force Air”). But for 1970, some exterior trim features were added to the W34 option package to create the Toronado GT. It’s mildly confusing: What’s the difference between the W34 and GT packages in 1970? None. They’re the  same thing.

Under the hood of the GT, there’s nothing in view to indicate anything special. Yes, that’s a 455 cubic-inch Oldsmobile V8, 4.125-in bore and 4.250-in stroke, buried in the plumbing and power accessories. The items of interest to provide the extra 25 hp are hidden inside. First, the intake valves were enlarged from 2.00-in to 2.07-in. And a sportier camshaft was slipped in with .472-in lift and 285/287 degrees of duration. This was the same cam found in the Olds 442 W-30 when equipped with automatic transmission and air conditioning, reportedly.

Meanwhile, the THM425 three-speed automatic transaxle received a torque converter with a higher stall speed and a more aggressive upshift calibration for a sportier driver experience. The editors at Car and Driver tested the mechanically similar ’68 Toronado W34 and found the performance stimulating, if hampered by the big front-driver’s curb weight of nearly 4,700 lbs. In their testing, the quarter mile came in 15.7 seconds at 89.8 mph.

On the exterior, the Toronado GT’s visual signifiers were subtle and few. There were three, actually: a badge on the corner of the hood, contrasting paint accents around all four wheel openings, and two small cutouts in the rear bumper for the dual exhaust outlets. But from there, the full complement of Toronado luxury options was available on the GT, and the choices were considerable. Packaging the W34 option as the GT was a success, as more than 5,000 of the 25,000 Toronados sold in 1970 were GTs. But when the Toronado was redesigned for 1971 with a greater tilt toward luxury, the GT was discontinued.