[Kevin in NJ]

Connect a Model A engine to a generator outside.

Run the radiator inside the garage to take heat from that and use the electricity to heat also. Probably make enough electricity to run your house too and sell some back to the utility.

Seriously now some thoughts.

What is the cost of electricity in your area and what is the difference in cost from gas to electric? Are you going to keep it heated all winter?

In my area electricity is fairly expensive so gas is the best way to go. You have to consider cost of installation vs how much you will actually use it.

For my 2 1/2 stall extra deep attached to the house garage I got a very big pay off putting in a well insulated garage door. You biggest bang for the buck is in insulation and cutting off drafts to reduce air exchange.

If you have a source, the shop my brother works at uses a waste oil burner to heat the shop. They do enough oil changes the shop is often kept too hot, but it runs 100% off the waste oil so there is no cost.

Check out your local craigslist for used heaters too.