engine speed and rear ratio question

[happyranger]

I have a stock (as far i know) 94 2wd ext cab ranger, it has the 3.0 liter and manual trans, the rear is the 7.5 with 3.45 ratio (according to the tag on the axle). tires are 225/70/14. What i want to know is do these engine rpms sound right for the matching mph

overdrive
3200 rpm = 60mph
3500 rpm = 65mph
3850 rpm = 70mph

4th gear
3000 = 45
3250 = 50
3500 = 55
3750 = 60
4000 = 65

these are all approximate since its kinda hard to write and drive in traffic

i'm wondering because i plan on changing to an 8.8 explorer rear and i want to go with either the 3.55 or 3.73, but i don't want the rpms to be too much higher than they already are. my estimates are about another 300rpm with the 3.73 and with the 3.0 liter i figure that's ok

thanks for any insight

 

[Beanmachine7000]

What you have written sound almost 1000 rpm higher than what my truck with 3.73's runs... I think your tach might be off... 55 mph should be about 2500 rpm... 3.73 or 4.10 would be a good ratio for your 3.0, though...

 

[martin]

Look at his tyre size.

 

[Beanmachine7000]

Look at his tyre size.

Doesn't matter, he should still be around 2400rpm at 55mph in 4th gear... I have 235/75's and 3.73's and I'm at 2500rpm at 55mph...