What coolant overflow/catchcan do I use with LS radiator?
 

I recently swapped in a late model truck radiator into my 82 Silverado. It doesn't have a radiator cap or anything. What do I do with the hose that normally goes to the overflow tank? Can I run it to my stock 82 overflow tank which is just a non-sealed container with a top? Or do I need to go get the overflow tank from the late model truck?

I'd think you'd be fine with your original.

Only problem with that is your cooling system would never pressurize and you'd end up boiling a large amount of the coolant/water mix you have. I wouldn't see a problem using whatever overflow tank you like as long as it has a cap that can seal like a 'vette version. Any make or model should do as long as the hoses hook up.

i ran original with mine...
tied steam line into heater hose.

A reservoir needs to be used that has a radiator pressure cap on it so the cooling system will work properly. Have the hose run from the radiator to the lower portion of the tank so it will purge air to the top of the can and when the engine cools, it will only pull coolant back into the system. A tank from a 1999+ GM truck works in this manner and could be substituted in the place of your factory tank.

Can I mount the reservoir lower than the radiator outlet? I don't have any place to mount my reservoir other than on the core support below the headlights.
BTW my reservoir came off a 2003 2500HD.