auxillary heater
 

is there some sort of secondary heater I can get for the inside of the cab?

Aaron

try replacing the 3o year old heater core and clean the heater housung and with a 195 thermo you'll have more than enough heat

Yes. But the electric ones are teh sux0r. You'll get more heat from the high-amp current draw melting wires than from the heat coil inside them :(

I agree with cdowns, a properly operating heater, assuming not to many holes in floor and some normal insulation, that heater would heat a small house LOL.

If you are not getting heat you should check to make sure you have low med and high on the heat fan..

RPM9100 what year and engine do you have? air or not?
Like stated above normal heat will drive you out of the cab on full and 30* weather outside.

It is a '70 with a big block and no air, I am just a little worried for the winter. it gets mighty cold here, -60 celcius sometimes.

Aaron

A 195* thermostat should keep you warm. If it is factory setup the return might be going into the radiator which will increase the engine warmup time but should give good heat once it is up to temp. A peice of cardboard over half of the rad when it is really cold would help. I am sure our other northern friends will help. The alaska crowd or BC, alberta, manitoba,saskatch, maine. They all get that cold.
Your biggest problem will be getting it started in that temp if you don't have a block heater.

Insulate the floor and make sure the door rubber seals well. Cold temps tranferred thru metal and cold air entering the cab from other than the heater system are the only things that can hamper a properly functioning heater system. Also, check the heater valve. It may be corroded. Does the heat lever operate smoothly with little resistence?