Depends on make and model of the engine.
No, but a lot more oil can cause other damage.
You can do some engine mods, but the simplest way is to drive it better. If you're turning 3.36s with a 12.8 engine, it is what it is.. you're not going to make much of a hill truck out of it.
Engine will overheat and seize
Yes, any GM V8 engine will FIT in GMC truck. It just depends on how much modification you want to do to hook it up and make it run. Yes, any GM V8 engine will FIT in GMC truck. It just depends on how much modification you want to do to hook it up and make it run.
Depends on condition
iIt will overheat and the engine will eventually lock up. The heat will do damage to the engine. How much is hard to say.
The engine will overheat and eventually seize. This will pretty much destroy the engine if it is driven long enough.
Depends on the engine and the work load being placed on the truck.
Depends on make, model, accessories, mileage, engine hours, and overall condition.
38 - 46 quarts, depending on what the engine is.
Truck mechanics make many repairs to trucks, depends on the location.