Once it's good and clean as you like it you can start putting it back together again. A word of wisdom - it won't be spotless. The engine is 50 years old. If you want to get all of the dirt off you'll need to do some serious scrubbing or just dip it in a vat of cleaner. If you just want to knock some more dirt of of her you can repeat this process since you already have the alternator and battery out.
So to put her back together you just go find your alternator and put it back in the battery tray. Be careful not to bang the pulley side around on things or you can damage the windings and/or brushes inside. Be easy with it.
While it's in the battery tray you can re-attach the little wire on the back.
Then set the alternator back in it's slot and run the long bolt and whatever stuff the PO put in there as a spacer. Remember that the larger bolt hole goes on the bottom, the smaller on the top.
Now place the top alternator bolt in but don't tighten it just yet. Just run it in there snug.
Don't forget the plug in the top.
Then slip the belt back on, making sure it is still on the other pulleys on the engine too.
Finally just tighten the belt. To do this you put a prybar (a crowbar in this case) between the engine and the alternator, prying it out until the belt is good and tight. Then you tighten the bolt on top. It's a little tough to do both at once but if you stand on the side of the truck and pull with both hands you should make it perfectly tight and keep it there. If you start the truck and it whines you'll know you didn't get it tight enough.
That's about it. You just washed your first engine. If you can do it, it's a good idea to let it dry for 24 hours before driving just in case you squirted water into the spark plug holes or something.
Now, don't worry if it didn't blind you with sparkly magical powers when you finished. It's not going to - it's 50 years old. You want a sparkly engine? You gotta scrub for that. Alot. My main goal was to kick the crud off so that it looks better and doesn't color me every time I lean over to fiddle with a spark plug wire.
Lessons Learned:
- You can reapply again and do it again. I tried it a second time and it had better results.
- Dirt is like an ogre. It has layers.
- Don't expect to strip it all off at once. Baby steps.
- Scrubbing an engine with paint on it can give you an engine without paint on it.
- Don't leave a 5 year old boy and a set of wrenches alone. Ever.