What RPM's are you @ 70 ?

[SportSter]

I just purchased a 94 k2500 6.5lT for a good clunker and boat hualer. I notice my RPM's are pretty high @ 70mph. What should the RPM's be?

[john8662]

what is it geared?

my 4.10 ratio nets me 2400 @70 in OD.

J

[6.5 Detroit Diesel]

RPMS@70MPH-2,200 with 35" tires. Buddies 6.5 with 4.10 and stock tires (auto) 2,400RPM @70MPH
Open your glovebox and look at the sticker inside, It will go alphabetically. Your looking for
GU6=3.42
GT4=3.73
GT5=4.10
Hope this helps ;)

[6.5diesel]

3.73 gear, 5 spd, 33in tires, 70mph-2100 rpm

[sailun]

3.42, 245 tires (stock), automatic, 70 = 1950 rpm

[billschall]

3.73 (according to the GT4 glovebox code) 265/70R17 tires, 70mph @ 2400rpm.

[DA BIG ONE]

3.42's, auto, 33" tires = 1800 +- @ 70mph.

[DennisG01]

about 2100 rpm's

[bmp34]

you want those 4.10's if your haulin on the highway. I have a 5sp and mine are 2500@70. I have 4.10's

[moondoggie]

Good Day!

Why guess?

rpm = mph [FONT=Courier New]

[JeepSJ]

Here is another formula for you -

mph = (rpm/gear ratio) * (tire dia/336)