54 GMC, S10 swap, OM617 diesel

[DieselRat]

Ive never been good at calculating that kind of stuff, and with no tach I cant tell you what RPMs I am turning... BUT the rear. I got. I pulled from the junk yard out of a 4x4 blazer i believe is 3:55. I can pull hills in 5th gear as long as Im not lugging it alone. I usually rev it out until I see about 10psi of boost then shift. Granted I have stock s10 14" wheels and tires so with a little taller tire I could see that slowing me up some.