At the risk of sounding like a jerk I want to give some of my thoughts as a mechanic for a novice reading this in the future. It's best not to flip an engine upside down on the engine stand to remove the oil pan unless you are planning on completely disassembling the motor. Although a little more difficult you should take it off with the engine in it's normal position because you have no idea what small bits of timing gear or whatever are in there, as the heaviest bits end up in the bottom of the pan not in the filter. Once removed then you can flip to make things easier to work on. This goes for auto transmissions also as rolling it upside down while out on the ground may lodge debris in a hydraulic valve and ruin an otherwise working tranny when it was removed. Same for carburetors if removing to do other work don't flip and drain unless you are planning on a rebuild. These are some of the very basics I was taught (Or yelled at for) by experienced Mechanics when I was a pup. When checking the health of a motor the easiest and best way is to do a compression test a leak down test and check the oil pressure. If you remove the engine to check it's health before doing these you really need to do a full teardown and measurements otherwise just looking at it form the bottom will tell you almost nothing about the health of the engine unless their is obvious catastrophic damage. Most of the wear in a cylinder occurs on the thrust side near the top half of the stroke which is completely hidden by the piston when looking from the bottom of the engine. Even engines with high miles will show original hone marks near the bottom of the bore. Also there are no provisions for adjusting Pontiac valves from the factory other than making sure the rocker arm nut is torqued to the proper spec. If you want to make them adjustable you can buy an aftermarket product called poly lock or an equivalent to make them adjustable. I know many people have flipped there engines and trans (hopefully not while in the car) and ended up ok but why play Russian Roulette with your wallet and time if you don't have to.