it is a Ford of Canada number for a V8 engine/transmission assembly used in a right hand drive big truck chassis, hence the C at the front of the prefix followed by the 18 and ending in the F. The same number should be on top of the chassis frame rail on the left side just forward of the front of the firewall attachment (although in some instances it would have been stamped on the right side of the frame near the front of the firewall).