Young and stupid? I'm not sure age has much to do with it as I am old and stupid. I replaced my exhaust Y-pipe and didn't remove the engine. I did move it forward about 8 inches, but both bottom exhaust bolts were all done by feel. I couldn't see anything. And laying on top of the engine really adds to being stiff and sore.
Just to change the sparkplugs, I need to remove both batteries, squat down on the battery tray and reach back along the engine. Luckily I have long arms.
The engine compartment looks spacious, but only a midget ...er....."little person" or a small child could get in there.
I actually went to the dollar store and bought a fairly good size hand mirror. I mounted it on a light piece of aluminum channel and then had another piece of channel a little wider so I could hinge it. Helps immensely to find the oil leak. I also tried a digitial camera, but no matter where I thought I had it pointed, all I got was glare from the flash and what is left of the oil pan paint.
Mercruiser has discontinued the oil-pan, and so far all I can find is a Sierra, P/N 18-0613 and a 4 piece gasket set, 18-0411. Wish I could find a pan in SS, but no luck so far. Wish I could find a 1-piece oil pan gasket as well, but again, no luck. Not sure about the pan and gasket compared to a regular SBC, but there seems to be a problem with the dipstick tube. In a Mercrusier, the tube extends all the way to the bottom of the pan for oil removal (has a threaded end up top to connect a oil removal pump). I can't see because of the starter, but I suspect the oil tube is different and somehow partially external to the block so regular SBC aftermarket stuff may not work.
I like your story about all the different sockets you used to fit rusted bolts. I've been there, but luckily not crawling around a boat engine compartment. Does build character though, doesn't it?
Moral: When you can't afford new stuff, and you buy old stuff, be prepared to work your arse off....i.e. that would be me!