Bob,
I have a heater that uses the coolant, but a different brand. Below is a photo of how I hooked up the heater. It is not neat or pretty but works. The goose neck, coolant outlet at the top of the head, is a special one that has a tap for the heater inlet. A tee is attached to the goose neck that has the bulb for the temperature gauge and a hardware-store ball-valve with a hose that goes to the heater. The return hose hooks to a special coolant inlet at the side of the engine that has a tap for the hose.
If you cannot find the special parts you can drill and tap for a pipe fitting. Use brass as it will not rust. Tap the holes a little and test the fitting. Tap more if needed. Use the Teflon tape to seal the pipe thread.
I can turn the system off in Summer to keep the passenger compartment from getting too hot. At the bulkhead there are two copper ells and short pieces of rubber hose to connect to the heater.
The tee at the goose neck is before the thermostat so the heater has first use of the engine heat.
I have a rheostat for the fan of the heater to control how much heating I get. I made a bracket for the rheostat. It mounts near the heater.
Years ago I saw an installation were someone used standard copper tubing with soldered ells. It was a lot prettier. He used short lengths of rubber tubing at the firewall so that engine vibration and movement would not break the plumbing.
I hope this helps you.
