there are 3 engines they show for these trucks
4G33, 4G52 and 4G54
mrfixit is probably right, it probably is a 4G52
but if you want to be sure look on the driver side of the engine, opposite of the distributor and look about half way down in the center of the engine block, there will be a rectangle square machined off place in the block that is flat, clean it off and look, it will have the model number stamped in that rectangle square area.