If it were me, I'd use the '84 chassis. The Blazer chassis is not bad but too short a wheelbase even for a short box pickup, you'd need to stretch it . That generation chassis isn't all that different than the earlier one and it will build up with a stock 4X4 height, all you need to do is not use the seprate lift blocks at the ends of the springs. That chassis is actually quite nice of you get rid of those stupid lift blocks and 1/20 scale wheels/tires. As far as the inner fenders go, cut the ones from the cab and use the ones molded on the chassis, they're correct for that generation pickup, the ones molded to the cab are not.