Timing Chain Cover

You'll need to drain the coolant first from the lowest point you can, there are drain plugs on the sides of the block if they're not seized in there. It won't hurt to drain the oil as you will have to eventually since antifreeze will get into it when you remove the waterpump and timing cover. When it's all reassembled I would probably run some cheap oil/filter on it for a short period ~30min. to get the oil hot and flush out all of the contaminants in the cheap oil change then replace with fresh oil/filter.
You shouldn't have to drop the oil pan. Don't forget a TC gasket set, it'll come with the wp & fp gaskets. I use FelPro.

Make sure you get a similar timing cover as they varied over the years - w -w/o timing pointer, revese flow waterpump, w-w/o oil dipstick hole, etc. and check the depth as there may have been different depths on the backside where the fuel pump eccentric spins. There were different depths on the 289/302 ones in later years and the eccentric would scrape if you used the wrong one, not sure if the 351W is the same.

I would suggest renting a harmonic balancer puller from the parts store, most rent tools for a deposit and refund in full when returned - NAPA, O'Reilly's, Advance, etc. I don't think you'll get the balancer off without it.
Jon

You don't have to remove the oil pan, but the front of the pan IS bolted to the bottom of the timing cover. Don't start pulling on the old timing cover until those pan bolts are out, otherwise you'll bend the front lip of the pan. The new timing cover gasket set will contain the front part of the pan gasket, which you should replace. Cut the old pan gasket flush with the front of the block on both sides, scrape old gasket pieces from front of the pan, and install new pieces using a small amount of RTV sealer where the new joins the old. Don't forget to stuff some rags in the exposed area of the pan to catch debris.

One other thing - not all timing covers are 100% interchangeable. Make sure your replacement has water passages that are shaped like those on the old one, to ensure that you won't have cooling problems (some later covers were cast with passages for the reverse-flow water pumps).

You should probably do a forum search for "timing cover" and absorb as much of that info as possible. Here's a thread to start you off:

http://www.stangnet.com/mustang-forums/824381-5-0-water-pump-alternator-belts-running-hot.html

Note especially D. Hearne's warning regarding the dangers of mixing front-engine-accessory bits and pieces.

Hopefully your TC is the same one that came on the block. I would check your casting numbers and date code to see what year your 351W is. The casting numbers and date code should be cast into the block at the rear right (passengers) bottom corner of the block just above the oil pan mount like this:


You'll probably need some gunk, a toothbrush and some rags to read it, bring something to write on under there or say it out to someone to write it down. Casting number on bottom, date code on top. If you need help decoding it just post here.
Jon