From at least 1955 through 1963 the first gear ratio for six cylinder Chevrolet & Canadian Pontiacs was 2.94:1, while the V8 versions had a 2.47:1 low. One exception was in 1958 when they used a 2.20:1 low on 348 cars, not a good idea on a heavier car for street use so they switched to the 2.47 low for 1959. The ratios changed on the V8 versions for 1964 to a 2.58:1 low. For 1966 the Saginaw boxes were revamped and made fully synchronized. The ratios switched to 2.85:1 low on sixes & 283s (& later 307) while the 327 / 350 cars had a 2.54:1 low gear with a ball bearing front input shaft support rather than the oil impregnated bushings of the others.

Axle ratios typically were 3.36 (Powerglide) and 3.55 (manual). O.D. was not offered in 1960 on Canadian cars but in the U.S. where it was, 3.70 was the only ratio. 348 cars with the Turboglide or Powerglide came with 3.08.

Cameron:  Thanks for the information.  If you have read any of my other posts you will have noted am installing a rebuilt 261 from a 60 Pontiac into my 39 Chevy Coupe.  I had originally intended to complete the drive train with transmission and rear end from an S10.  When I harvested the 261 I removed a number of items from the car including the 3 speed standard tranny (rear end was shot).  From what I have read there are some challenges relating to adapting the S10 tranny to the 261 engine.  In keeping with my philosophy of using the KISS method I suddenly had a moment of clarity yesterday and realised the simplest and least expensive transmission solution was to use the 3 speed taken out of the 60 Pontiac - not to mention that the clutch I retained from the Pontiac appears to be fairly new and in good shape.  I now only need to acquire a suitable rear end;  hence my request for the gear ratio the Pontiac diff. would have had.  If the diff./tranny combo in the Pontiac worked well for that car, no reason why it won't provide good performance in the Chevy (not really interested in huge performance - only want to be able to drive the car at modern highway speeds). 

Gary Hammond, Lockport, Mb 

39 Chevy Coupe, 40 LaSalle, 46 De Soto, 47 Dodge 3/4 ton Express (currently a project), and 51 Dodge B3C 3/4 ton Express

Glad to help out. That 39 Chevy sounds really nice and a 261 will be one of those "hidden" upgrades, especially over the old splash lubrication 216. That 40 LaSalle look positively majestic.