What engine of other cars could fit in Chevy caprice 82-85,

Buy new blower motor

You will need to replace the line.

Could possibly have a clogged radiator, Which engine does your caprice have? You also need to make sure all air is purged from the system.

When does it over heat, all the time, or just when idling?

go to autozone.com this should help with the schematics if not then go to a auto part store and buy a book the book should cost around 11.00$ and should fix your problem :)

If you are set on using this engine for its increased power and fuel efficiency, the only way you will realize these benefits is by changing the ECM/PCM from the engine donor vehicle to yours, put the 90 model engine's throttle body back on it, use the engine wire harness from the donor vehicle--in other words, the engine has to think it's still in the Caprice, and the only way to do this is to put the Caprice electronics and fuel management system (throttle body) back on it. If you have to modify the throttle linkage, the kick-down/TV cable, to make it work, then do it. Also, you will have to put an Oxygen sensor from a 90 Caprice into the manifold/collector/crossover pipe of your vehicle, and not one for the 87 truck. If it wont fit, plug the factory hole on your truck's Oxygen sensor location with a threaded plug using high-temp thread sealant, cut/weld in a proper-threaded orifice for the Oxygen sensor from a 90 Caprice. If the Caprice had two Oxygen sensors, you will have to put one on each cyclinder bank's exhaust outputs.
Swaps such as these are great if all the details are attended to, but headaches if you just try to throw and go.
If you do all this, the codes will not come back after you reset them, the engine will run great, you will have better power and greater fuel economy (the Caprice and the Blazer weigh within a couple hundred pounds of each other), and you will have a 1987 K5 Blazer which "thinks" it's a 1990 Caprice.
And remember when buying engine parts in the future to tell the counter guy "It's for my other car--the 1990 Caprice."
You get less **** out them that way.

Providing that the valve covers are the same, the engine should fit. It would be easiest if both transmissions were identical but you can use a 350, 400 or even a 700r4 in there with some mods and a crossmember move and possibly a driveshaft mod. You will probably want to swap intake manifolds and all brackets for stuff up front as well.

to put a later model engine in that car,the swap you described will require a complete wiring harness change and computer and all electrical that goes with whatever late model engine you go with.

You need to buy an adaptor. You can buy them at Wal-Mart for about 10 bucks.

if you have the engine out itheir is a vin num stamped on the rear of the heads ,olso if its a small block shuch as a 350 327 305 or even the 400 small block90% of the engine parts are enter changeable,
their shoulf also be a vin number stamped on the block right above the top bolt of the water pump on the drivers side

go to alldata.com and just register and ull be able to get it true themhope this is helpfull