Nope!
The 6.2 l Detroit Diesel has allways the same block, crankshaft, tie rods and pistons, whichever engine code it is.
J stands for heavy duty emmission of 1985, 1986 and 1987.
C is the low emission level for light duty trucks. Difference is the cam shaft and different valve size in the heads.
Injection pumps are basecically the same excempt the features for medium or high altitude (not used by the military) and
allways J-pumps! (Standadyne DB2
.
Power output is allways the same. The military states 135 HP net at 3600 rpm for the CUVC , here means the 2 102Amp gens charging fully. The label on the air filter states, depending of the year of manufacture, 150 or 155 HP.
The truth is 110 kW/150HP at 3600 rpm.
Hummvee is the same, however the manual states 110 kW / 150 HP at 3600 rpm. If the hydraulic fan blower cuts in, you suddenly loose 21 HP, this feels like somesone stepped on the brake.
Thats it.
Wolf