[brucepick]

I don't have time to do a full writeup now but these key points should cover the bases.

I installed the heater canister where the AC condenser and fan used to be. If you don't have a belly pan blocking access from below, it might fit near the lower air intake snorkel.

Supply to heater is from a tee inserted in lower radiator hose, low down at start of its vertical run. Tee is model 28113 from Kats Heaters.

You could get the supply from the radiator petcock, but I think you'd need to permanently plug the drain opening while threading a hose adapter into the petcock threads.

Outflow hose from heater must rise continuously till it enters the head. It enters the "hot" heater hose below the distributor; I used a tee distributed by Gates, the hose people. Did not use the tee provided with the heater (too large for the location). Remove the dizzy to get access there, replace the shaft's o ring seal while you're at it.

Plumbed as described above, heat from cabin heater will be reduced because radiator-cooled water flows to the cabin heater when driving. I hope to install a partial plug in supply hose, or a heater control valve in the output hose to be opened only when running the block heater. Temporarily I'm clamping the hose with flat nose vise grips.

The heater (model number in first post) has a backflow prevention valve and thermostat shutoff.

I put foam pipe insulation over the hose. Too close to exhaust manifold = melted foam.