1997 Chevy Cheyenne K2500 (8 lug) 5.7 vortec/ 4L80 tranny /10.5 14 bolt rear end with 4.10 gears and a detroit locker/ 3 inch body lift/ 2.5 inch suspension lift/ running on 315/75 r16 front diff 9.25 ifs with 4.10 gears i choose the k2500 for the front diff the k1500 has a 8.25 ifs and the k2500 8 lug has a 9.25 ifs you can put a locker in the 9.25 ifs, but you can not put a locker in the 8.25 ifs, also the front diff is the same as the H1 or the H2 the 4L80 tranny is the same as the H1 the rear diff is heaver than the H2 the H2 rear diff is a 9.5 14 bolt c clip style while the some of the K2500 come with the 10.5 14 bolt full floater like mine does, i do have a hydrogen kit for this,(http://globalenergydevices.com ) which raises the hp to about 350 hp and fuel about 25 mpg with 410's this is still a work in progress