rear ratio changed 1964 commander 170 ohv

[Wheel nut]

I changed out the rear end from a 3. 73 to a 3.54 running 205 75r 15 tires no overdrive with a 170 ohv now my speedometer is spot on with my gps
around my part of the country northwest missouri i thank this is going to work well engine has plenty of power that makes it a 55 to 60 mile car without all the rpms if a 6 cylinder automatic can handle that rearend i can not see why a 3 speed standard would have any problem

[StudeRich]

Sounds like a good improvement, FYI the 3.54 was not Standard for the Automatic, the 3.73 was for both the Standard and the Flight-O-Matic's in '61 to '64 OHV Sixes.

They will overheat at 70-75 MPH and crack the Head without Overdrive, so as long as you keep it at mostly 55 and sometimes Short periods of 60-65 and WATCH the Temp. Gauge, you will be fine.

Your Car came Standard with 600X15 Tires (closer to P185/195X15) so the larger Tires slowed the Speedometer down, it either was not very correct or may not have the correct Pinion Gear for the original 3.73.

They were never dead accurate usually a bit Fast, like 5 MPH.
But, it has never been an exact science, because the different tire brands are not even the same diameter in the same "Size".

[64studeavanti]

A little less acceleration when starting from dead stop. The automatic has the torque multiplication effect of the converter, effectively lowering the gear ratio.

[m5studie]

Wheel nut How is that 354 working in your car. Please call me at 608-698-1771 Terry

[StudeRich]

Is it mostly flat where you live, like where Rickey lives ? If not that could be a problem.