I've got a '90 x-cab pickup, 3.0, 5spd and was wondering what rpm should I be at going 70mph. I'm usually pushing 3200. That seems kinda high to me. As for as I know I've got stock gears and I'm running 31" tires. I'm only the second owner and I dont think the old guy I got it from did anything to it.

 

did it come with 31's stock? whats the gearing?

If it didnt come with 31's stock then you will be doing faster than 70 when the spedo says 70.

 

MMA's right-- you'll be doing 3-5 mph faster than what the spedometer is telling you. I've got a '91 22re with 31's on-- my tach registers about the same as yours at your speed. I'd say it's pretty normal. I've found that I get my optimal mpg's between 60-65 mph.

 

You can try the calculators on this page to find out your gearing:
http://www.4crawler.com/4x4/4LoCalc.shtml