Coolant Heater (36mm Freeze Plug) - Various Applications:

Fiat Hesston

Allis Chalmers

Oliver White 

Minneapolis Moline 

Long

rpls: 764161, OW70746

NOTE: I've had some heaters bottom inside the block. Some of the block castings must be rougher inside than others. ALSO, I have seen the heaters themselves that have been made with difference clearance from where the o-ring groove is.