Vintage Road & Track review: 1966 Plymouth Barracuda S – Disc Brakes (And An Automatic) Do Make A Difference

This review is something of a follow-up to an earlier review that R&T did with a 1965 Barracuda S. That one lacked the disc brakes that the ’66 had. But there was another difference: the ’65 had the four speed manual and this ’66 came with the Torqueflite automatic, which makes for an interesting comparison.

The disc brakes were supplied by Kelsey-Hayes, and had noticeably less fade then the front drums of the ’65. But the system’s behavior in a panic stop test was anything but good. The rear drums locked up and there was drastic loss of directional control. The front-rear proportioning was far from ideal, but this issue would plague many American cars for years to come. What they all lacked was a height-sensitive proportioning valve, which increased or decreased pressure to the rear brakes depending on how much or little weight was on the rear axle. My Peugeot 404 had one, and it worked like a charm. I don’t know if American cars ever got around to using them before ABS braking made that issue moot.

The performance with the automatic in comparison to the previous four speed manual was a bit disappointing. It took 1.8 seconds longer to cover the 1/4 mile and was 5.3 seconds slower to 100 mph. Both had the same 235 hp four barrel 273 V8 and the same 3.23:1 rear axle ratio. Not surprisingly, the automatic car was a bit quicker off the line and to 30 mph. Its 0-60 time of 10.3 seconds is decent but not exactly quick.

Torqueflite equipped Mopars had a rep for being just about as fast as four speeds, but that depended to varying degrees on the specific engine. The rather small 273 V8 may not have had the torque to compensate for the automatics losses despite the advantages of being faster out of the hole.