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Ronnieroadster · 10-19-2020, 02:05 PM

Using a Mark Williams gear ratio computer the RPM reduction you will see at 60 MPH going from the 411 to the 378 would be 200 RPM. Now if you go to the 354 ratio the RPM is now 2400 RPM lowering 200 more RPM for a total of 400 RPM less when compared to the 411 gear. The calculation I used was based of a 30 inch tall tire. Making a decision to change the rear gear considering the time and expense involved giving some thought to going to the next step which would improve economy a lot might be a wise decision. Any stock flathead would have the torque needed if the 354 gear ratio is being used.
Ronnieroadster

10-19-2020, 02:05 PM	#13
Ronnieroadster Senior Member Join Date: Dec 2010 Location: East Coast in CT Posts: 1,524	Re: 1936 Ford rearend gear ratio and speed Using a Mark Williams gear ratio computer the RPM reduction you will see at 60 MPH going from the 411 to the 378 would be 200 RPM. Now if you go to the 354 ratio the RPM is now 2400 RPM lowering 200 more RPM for a total of 400 RPM less when compared to the 411 gear. The calculation I used was based of a 30 inch tall tire. Making a decision to change the rear gear considering the time and expense involved giving some thought to going to the next step which would improve economy a lot might be a wise decision. Any stock flathead would have the torque needed if the 354 gear ratio is being used. Ronnieroadster __________________ I use the F word a lot no not that word these words Flathead , Focus and Finish. "Life Member of the Bonneville 200 MPH Club using a Ford Flathead block" Owner , Builder, Driver of the First Ford Flathead bodied roadster to run 200 MPH Record July 13, 2018 LTA timing association 200.921 in one and a half miles burning gasoline. First ever gas burning Ford flathead powered roadster to run 200 MPH at Bonneville Salt Flats setting the record August 7th 2021 at 205.744 MPH Last edited by Ronnieroadster; 10-19-2020 at 02:14 PM.