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The last of the big, brutal American four-speeds


#1

Two-ton-plus, big-block, four-speed, full-size American cars were big and brutal in the 1960s. Then, without a whimper, most faded into oblivion after 1969. These dinosaurs from Detroit’s more recent past were, indeed, still available to buyers who needed that extra connection through a shift handle and clutch pedal—even in four-door versions—until 1970.


This is a companion discussion topic for the original entry at https://www.hagerty.com/articles-videos/articles/2018/04/18/big-brutal-american-four-speeds

#2

What a great article…especially for us “WW2 war brats” that grew up drooling on 409 Chevys, tripower Pontiacs, cross ram MoPars and solid lifter 406 Fords…the fastest car in our Iowa county (for a long reign) was a '60 Pontiac Ventura hardtop with the 425A tripower engine backed up by the 4 speed hydramatic transmission…super low first gear provided a hole shot of biblical proportions which left most competitors wondering why they were several car lengths behind right off the line…allowed to look under the hood was a religious experience for those whom worshipped the lucky owner of the latest hot car…the first GTO in town did not have positraction and would lay down long black strips of rubber at command…the GTO accelerated the end of the big body cars and ushered in the muscle car era from every manufacturer…great memories of long ago when we were all broke and spent every dime we could find on engine mods…


#3

GM used the Borg-Warner T-10 up to '65, I think, when they developed their own 4-speed. Our '62 Impala SS 409/409 is so-equipped.


#4

Chevrolet introduced the Muncie 4-speed in 1963… M20 “wide” ratio and M21 “close” ratio…

Despite the monikers, the ratio difference (RPM drop) from 1st to 2nd and from 2nd to 3rd was the essentially same… the “wide” M20 had a wider ratio split and larger RPM drop between 3rd and 4th gear, while the M21 had a ratio drop similar to the 1-2 and 2-3 drops…

Overall, the M20 had “lower” ratios, which worked better for highway gears (generally 2,73, 3.07, 3.31 and 3.55:1 rearend ratios). The M21 was used for 3.55, 3.73, 4.10, etc…

M20 changed ratios slightly from 1965-1966…

M22 “Rock Crusher” had the exact same “close” ratios as the M21. The M22 used gears with less of a helical angle to then, not only increasing the strength of the gears, but reducing the fore and aft stresses when road racing (up and downshifting)…

The M22 first became available in 1966, in Corvettes, and only 12 (twelve) Chevelles…


#5

I still have the '66 Plymouth Sport Fury convertible I bought from a salvage yard in '81. 383 four-barrel with the NP A-883 4-speed. The MoPars required a tunnel hump modification at the factory in order to accept the four-speed; one way to determine if a four-speed car was factory-built.

I used to work with a guy back in the early '90s who drove a '66 Catalina 2+2 hardtop with a 421 and four speed. We often wondered who would win if we were to drag race our two cars. He had more cubes, but also more weight. We never got around to pulling off the race, though…

Growing up in the '60s, my father didn’t trust automatics, and so in addition to several European cars with 4-on-the-tree (Peugeot, Mercedes, etc.), we were treated to several American (or, more accurately, North American) iron with three-on-the-tree. A '65 Catalina coupe, a '64 Canadian Meteor 2-door sedan (with Breezeway window!) and a '71 Mercury Meteor Rideau 500 wagon. That last one came about because we needed a full-size American wagon; my father tended toward Mercurys, and the only way to get a new one with a manual transmission was to go to Canada.