X2. Go roller for sure. As for heads, I found 5007950 Mopar R/T heads with 2.02/1.65 valves that flow like crazy. You can mount either timing cover on either block. The cams will change, as the roller block cover has no fuel pump mounting. Serpentine drive belts are standard on rollers, but vee belt drive water pumps are available for CCW rotation. Roller block pumps must turn CCW. My cam is a very torquey Mopar purple shaft with a spider lifter retainer which adds no weight to the lifter like tie bar lifters. My intake is an Edelbrock Air Gap which gives awsome low end performance.