VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 tips for lowering engine rpm on freeway

hi
what is the best way of lowering the rpm omn the engine wen driving on freeway.
i have an total stock 1939 chevy super master.
is it easyer to change the gearbox or rear axle?
all tips is welcome.
thanks
johnnyrobin
norway

Ring gear and Pinion needs to be a higher ratio. That's a common problem.

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warning.... $$$ Big Bucks

3:55 is the best for the highway

First off Johnnyrobin Welcome to VCCA we have folks here that can help you with all of your questions about vintage Chevrolet's.
Now to your question...You have to change the gear ratio of the rear axle to be able to run higher speeds on the freeway. The best for this would be to change the rear end ring & pinion gear ratio to 3:55.....Good Luck..& welcome aboard...ED

Is there a 3.55 made for 1939 passenger cars? Thought that was available for 1940-1948 only.
Install a 3.73 rear end which was used in 1937-1939 Master 85 cars ( cars with front leaf springs)....made a world of difference in my '39.