Looking for a good set of 3:23 gears, anybody got a set? Also question, what rpm should I be turning with those gears. 70 442 with auto trans. Thanks

 

Engine speed also depends upon the rear tire height. The same gear ratio (3.23:1 in your case) will translate to different engine speed depending upon the rear tire height. Taller tire = lower RPM and shorter tire = higher RPM.

 

There are several online calculators you can download and use if you know the variables listed above. Here is a link to one.

Engine RPM / Engine Speed Calculator
https://www.crawlpedia.com/rpm_gear_calculator.htm

 

Ken, you are running the same size tires and the same diff ratio, I am turning about 3500 at 60, that seems high to me, maybe my tach is off, what are you turning at 60? Thanks, Dave E

 

Yeah, that is a bit high. My car used to turn 3400-3500 at 70 MPH with the short 245-60-14" tires. I don't recall the highway RPM with the 245-60-15" tires but on surface streets going to work it is around 2200 RPM @ 45-50 MPH.