Rotella, Like Orange Says above.. Same oil i use in my Scouts. It has the higher zinc content that helps the guides last longer. The 71 already has hardened valve seats, so there isn't a need for lead additives or substitutes in the gas, but the extra zinc in Rotella will help all the 'oiled' parts. You'll also benefit if you can run Ethanol free gas in it, as all the fuel line is from pre-ethanol days, and will deteriorate those lines, there is a particularly long Nylon line that runs from the gas tank to the fuel pump that will dry out from it, I usually replace that one with steel.
Great deal on the service Manual!
On both the turn signals and wipers, Make sure they have a good path to ground, Number one cause of gremlins on a Scout II. Also the wiper (And headlight) switches can get dust in them, a good spray through with electrical contact cleaner can help. The grease in the wiper motor can get hard over time, If you'er up for a project, tearing that motor down, cleaning it out, and putting new grease on the bearings/bushings can help it go much smoother and faster.
Do you have a Dana 30, or 44 in the front? stock was a 30, but a lot ended up with 44's as options... If you can find the knuckles from a later model disc brake axle, you can swap all that stuff over to your current axle. Of course, if you can find a whole later axle with discs on it already, that's even easier, but you'll probably have a tough time finding one with both 4.10 gears and dis brakes.
On a 71, if it's still got the original distributor, that means it's got Ignition Points, (Oh Joy!), And that is likely why it runs like crap... Replace the points and re-gap them and it will help a lot. But if you can run down a later year Prestolite Distributor, that will relieve that issue. If you can't find a Prestolite, see if you can find a Pertronix Igniter or a Crane fireball ignition for it..
Truthfully, if you're only going to use it as a weekend fun type vehicle though, points aren't that bad, you just have to get used to setting them, and burnishing the points (Run an emery board through the contacts) every year or so.