Hey Old54truckluvr,
Yes you can replace the cam with the engine in the vehicle. You will have to remove the grill and radiator from your truck in order to remove the cam. As an alternative to removing the grill and the radiator you might want to consider pulling the engine to replace the cam.
It is sort of a toss-up as to which method you choose to use. It is much more easier to work on the engine when it is pulled from the vehicle and mounted on a stand. However, it takes just about as long to pull an engine as it does to remove the grill and radiator.
Just take your time and follow the procedure in the shop manual.
Good Luck,
Jon
P.S.
If you block has not been modified so you can remove the timing cover without removing the oil pan you will have to drop the oil pan to get at the two timing cover bolts located inside the oil pan. I learned this the hard way when I was an impatient rookie replacing the camshaft on a 216.
