kawi600

Truck shows 2250rpm at 70mph. Im guessing 4.10's
Which leads me to wonder if its terribly expensive to swap out front and rear ring+pinion sets to lower the gearing. My fuel economy is really bad.

Racer9

Jack up the rear end, put it on jackstands (safety first). Mark the driveshaft at either end, near the yoke, just so you have a solid reference point. Mark the tire near another reference point, rotate the tires 1 revolution while counting driveshaft revolutions. The driveshaft will spin just over 4 times with 4:10 gears, or about 3 1/2 times with 3:55's, or about 3 3/4 times with 3:73's. There should be a tag on the housing, or inside the glove compartment, but if the gears were changed, and the tag wasn't, it won't matter.

hotmopr

My 95 has a tag on the bottom side of the hood. It will tell you your gear ratio and if its a limited slip plus some other stuff. Next time you open your hood--Look up.

Flashpoint

Look in your glove box ,should be a sticker that tells . If your tires are 265s sounds like 4:10s mines pretty close to that at 70mph and im sure mine has 4:10s

plow

Mine has got 4:10s in it and at 2000 rpm im running 60 mph in 5th, 80 mph at WOT.