D318 Head issues

The early heads can be bored out to receive the larger diameter glow plug chambers. It's either that, find a later head or run without glow plugs.

The flame thrower is called a thermostart, probably could put in a couple of them in the block-off plates over the openings where the pony exhaust runs through the intake manifold. You would need to connect a fuel line from the fuel filter tower to the thermostart units. The ones I have seen have been on tractors with an injector return line which was convenient to Tee into. There is a block-off plate on the rear of the filter tower where a return line is attached on some industrial engines which would be a convenient place to tap in on your grader.

Here's a link to a google search page which should help you find thermostart units.
https://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4GGHP_enUS424US424&q=thermostart

Alternatively, you could use a grid air heater installed in one of the joints in the air intake pipe. These are common on Cummins 5.9 engines in Dodge trucks etc.

Might have to use 2 of either of these units connected in series to handle the 24 volt supply or find a source of 24 volt units.

Or install an electric ether injector or spray the can yourself. I really like to spray it by hand whenever possible, it gives me more control over the total amount and the rate it goes into the intake. Ether goes right through an oil bath air filter unit with no problems.