Is always nice to see a problem resolved. Just a bit ofr info for your cam as i just did mine on your same hp engine.
You will need to remove to push rods by simply pushing the rocker arms down to release the pressure. The cam is located at the bottom of the motor, so you will need to the whole thing upsidedown and remove the 10 case bolts.
The cam just pulls staight out from there. The new cam will come with new solid lifters and i would'nt be suprised if your lifters look perfect. When installing the new cam simply line the dot on the crank timing gear to the dot on cam gear. Its idiot proof.Your case gasket goes on dry and bolt torque is 200in lbs. You might as well change the lower crank seal while you have the case off unless you feel its fine. 2 things to look at while your closing the case. The crank seal tears easily so use lube and take your time. Watch the postion of the governor paddle and make sure it in the right position. The point on the governor gear must push on that paddle. You will see what i mean when you look at it.
Good luck