Andre,
The 6.2 diesel was something of a dog. I think the power rating in the 1988 chevy pick-ups was 143 hp and about 247 ft lb of torque. you could squeeze that out of a healthy six probably with similar gas mileage.
TWE I dont know how you get that kinda mileage from a 5.2, we have a 96 grand cherokee with that motor and it's 15-16 on the highway tops. This is with stupid AWD and 3.73s though.
