Thanks for your input and experiences -
Pulling the engine is not an option.
"Boltr#43" - I'll paint the pan and timing cover in place. (Originally thought the timing cover was an easy removal)
"51 aston" - Yes, this is gonna be a tedius job! I'll remove everything that I can before painting the block.
"Builder" - I agree about pressure washing, but my pressure washer died last year. I Gunked it yesterday. Used a
$7 siphon engine cleaner from HF to cover everything with Gunk. Did a good job of getting it in crevaces and tight places. But "blasts away dirt, grease, and grime" is an exaggeration!. Standard water hose pressure cleaned it up pretty well. I'll Gunk it again and maybe borrow a pressure washer. Spot clean with acetone as needed. Luckily, the engine and frame were fairly clean to start with.
The "while-you're-at-it" syndrome is starting to kick in. I may scuff sand and paint the inner fenders, too.