I saw this also. I am sure he is refering to the Turboglide transmission. It was the only "automatic" available with the 250 H.P. 348. Chevrolet refered to it as "Tripple Turbine" in some of their literature as the plantary gears put it through three different phases in the torque converter. All gear reducton was done through the converter turbines and no shifts were felt. If you could listen carefully you could hear a slightly different planet carrier gear noise change from step to step. Owners complained because they couldn't feel a shift like the CVT's of today.
The 1957 and 1958 Turboglides were very problematic.....The new and improved 1959-1961 were as good as any automaic in its day, just that a lot of techs didn't like to work on them....or didn't know how. You know how that goes
The T.G. worked best behind a 348 engine because it required more torque. In 1959 the T.G. got the 3.08 axle ratio so at least the highway milage would be satisfactory.
Glad you mentioned ths. I was thinking of putting a "correction" in the G&D but that would not be proper.
Note-in 1957 the TG was available on any 283 with a hdraulic lifter cam, 185,220,245 and 250 HP.
In 1958 you could get the 250 HP 348 with P.G. or T.G..'59 and up the 250 HP was available with TG only.
From 1960 and up a P,G. was available in a special police 348 305 HP version with a 3.55 rear end.