[highperf4x4]

Since you're pulling all the accessories off the front of the motor anyway you can take the 4 bolts out of the water pump and take it off to drain the coolant. That will get your coolant below the head line. That's how I do it when I'm pulling them in the vehicle.

As mentioned before, pull the intake first and spin the motor (take the spark plugs out and it will turn easy). If the lifters for that cylinder aren't moving as far as the others then it's the cam and you need to pull the motor and start from scratch.

If you're going to do one head, then you should do them both. If the engine is old enough that it doesn't have hardened valve seats for unleaded gas then you'll want to have them installed. If the engine is high mileage then you can expect it to smoke after you do the valve job as you've increased cylinder pressure thereby increasing "blowby"

Definitely put some clean rags in the cylinders before you start cleaning off the old head gaskets but I wouldnt' drain the oil until after you've cleaned the gasket surfaces. Whatever falls in the motor will drain out better with the oil. I'd also flush the lifter valley with deisel fuel while you have the drain plug out. Run your finger around in the valley while you're at it to see if you find any copper. Copper is in the "core" of your bearings. If you find any then your bearings are in bad shape and you should pull the engine and rebuild it.

Another thing to check while you have the heads off is the "ring ridge". Your piston rings stop about 1/4" from the top of the cylinders. If you find a pronounced "ridge" there then your cylinders are extremely worn and you should pull the motor and rebuild it.