33 & 34 Pontiac

[Gregory Crosby]

Does anyone know of a way to get a higher ratio for the differential of my 1933 Pontiac Cabriolet. The pinion in it now is marked #467 9-40 2-33n ? I once saw some literature about a choice of: Hill; normal & plains rear gears. I know the some chevy pickups used the same type of torque tube rear end. I am also looking for a trunion joint/universal joint for the 33-34(torque tube/trans conector). I may have a complete 34 car minus the body for sale. I believe I will have it startable soon. I am interested in anything to do with 1933 Pontiacs

[Guest]

According to the parts manual that is the only ratio available. My Pontiac has hotchkiss drive so there are quite a few diferences in the differential but I seem to believe, but do not remember and cannot prove now that a 48-53 approx chev crown and pinion would interchange. When I replaced my C&P the first time I was working for a GM dealer and matched up a gear set and I am sure it was from an early 50's chev. I think it is posssible that one from this eara would fit but am not sure.

My original rear end lasted about 180,000 miles, my second one lassted about 170,000 miles and the third on is still going at 135,000. My original rear end was 4.3 to one and the next two were 4.5 to one. I still have no trouble driving at 60 mph which runs the engine at 3100 rpm. It will pass 70 mph but seems to be straining at anything over 65 (3450 rpm). I have a 3.9 to one rear end but am wondering is that would be too low a ratio. I think maybe the power curve is too low and that I probably would not have the power to reach the same speed. I am thinking of putting it in just to try but am not sure if it's worth the bother. Having an open driveshaft it would be easier to install and overdrive for me.

I really would check the power and torque curves before you decide to change your ratio.

[Pontiac59]

If the Chevy gears work, you can get down to about a 3.55 by using a 52-54 Powerglide car rearend gear. The manual those years is about a 3.70.