I don't know of too many engines of this age that don't have 1/2 inch or better of grease oil and grime on them. You should remember that when you clean the engine off and/or pressure wash it, you may make it leak worse.
A cherry picker is still less expensive than a mechanic to pull the engine for you. If your engine is dead in the water in the truck, what have you got to loose with the engine out of the truck (with the exception of some time and space). Taking it out isn't nearly as hard as putting it in by yourself. Just don't try to leave everything intact on the engine before to pull it. Take off the carb, distributor, fuel pump, fan, etc. Lighten the load and minumize the risk of banging it against something and breaking it.
You say you have experience with wrenching on motorcycles. This is just another mechanical object with similar principles (of sorts) but the parts are just bigger, heavier, different and more pieces (maybe).
Get a service manual, pull the engine, clean it and the engine compartment and get another car/truck freak to help inspect it. Straighten the oil pan gasket surface read some "How to" engine rebuild books for assembly and cleaning methods.
We will certainly entertain you with answers to your questions. You can also get pictures on line to make situations clearer for us.
The trick is knowing who to listen to.
You aren't alone here on the Stovebolt pages. Most of us have been at this point. Some will never get there.
The only person talking you out of anything is you. You get to choose to be a doer (Let's do this!) or naysayer (I can't).
Keep us up to date, and good luck.
