Hatfield, no draining of any oil. Just the timing change cover then loosen the sensor. I cleaned up the area with just a clean rag and then put the gasket on, the shiney new timing chain cover back on and the shiney new bolts. This is where an extra hand comes in handy , trying to get it back together.
Make sure the gasket is on nice and straight and not pinched.
I got mine from Creasy's and the suggested bolts(by them) You really should get them. But they don't do it anymore, but Schroeders in NC still does the chrome stuff, you could check with them. Their # is in wing world 1-800-445-5934, maybe they have the bolts. Good luck and this is a great addition. Sure pretties up the front. Joy
Mine cost 125 for the cover
30 for the bolts
10 for the gasket
and 200 til they got the exchange back
Hope this helps. Joy