Need a range of advice... :)

[CamraMaan]

So I've had a '78 Chevy C10 (manual, 2wd, 250 inline 6) for a long time, and two days ago bought a '79 GMC Sierra Classic 35 Trailering Special (2wd, 1 ton, auto). With 10k miles on its rebuilt 454, about 2k miles on a rebuilt tranny, and a very nice interior (and straight body), all things considered, the price of $950 was way too good to pass up. But I'm new to the truck, and there are some problems with the truck that I need to fix, and not all the answers are easy to find out there. In no particular order...

This has dual tanks, but the ability to switch tanks is "broken". I'm stuck using the right tank, and the gas gauge doesn't move from about 1/4 tank, which makes me think it might be showing my left tank. But I have no idea whats going on with that, and I would really appreciate having a working gas gauge, nonetheless the option to use my left tank, since I ran out of gas the first night I bought the truck....... rude awakening. Any ideas/advice?

Next, the truck has A/C, but it doesn't work. And I mean nothing works, not just the A/C. Flip the switch on, no blower motor hum, no air movement, etc. Fuse? Blower motor? Short? I can obviously replace the fuse, and the blower motor is easy too (or at least it was on my '78, but that didn't have A/C), but I'm just curious if there are any other ideas out there that I may be forgetting.

Windshield wipers... need new motors, and would like new arms as well... I hate the flimsy metal arms, because at freeway speed (65+) with nice/expensive wiper blades, they just hop around and don't get the job done. Anyone know of a way to upgrade the wiper blade arms? Maybe a swap from a newer truck?? And any recommendation of wiper motors? I'd like to buy new, versus the scrap yard, but quality and inexpensive never hurts!

The truck already has headers, and sounds like it came stock around 230HP and 360Tq, and I just bought an Edelbrock top-mount air filter assembly. But I may want to upgrade the carburetor down the road. Anyone know what the stock carb's CFM is? What's the max recommended CFM on this engine without having to change any internals, just bolt on, adjust, and go?

I have every desire to drop the truck, since it has a 4x4 stance, but are there any lowering kits for this thing out there?? Seriously, I'm getting skunked in my searches. Would love to drop about 2-4" both front and back, or somewhere in that ballpark...

And along with the drop, I would like some more performance oriented tires, versus the (new) 80psi towing grade tires already on it. This has 16" 8-lug aluminum wheels, and I'm fine keeping those, but what are some tire recommendations? Assuming it will be lowered. My other truck already has the tires/look I want, but its a 5-lug bolt pattern with 15" wheels... and with that I went with a slightly larger performance tire on the rears.

And last, what gear ratio does this truck have? And what's recommended for better mileage, without sacrificing too much of the fun, but also assuming more power could be coming in the future?

Thanks!!