Still searching around for this. T the motor is a 617 from an early 80's 300d Cant remember the engine code off hand as I am at work, 905 maybe? the cam # is 8 I know.

Trying to think how to remedy this if I can"t find the correct adapter: As for now Im thinking about drilling out the stock plug to where the new plug is a sliding fit then JB weld it into there. Problem is, it wont take that much torque to tighten it back in. With the right sealer on the threads this might not be a huge issue. Other issue, if it goes bad it probably won't be coming out very easily. At that point I think I'll just get an inline hose heater from TSC.