If it is a 1978 4/4 it is likely a Ford 1600 drive train unless someone has done a transplant on the car. I had the same problem with my 1981 4/4 (same Ford) and sourced one from a Lotus shop here in the US. It wasn't easy to find. The Ford 1600cc engine was used by the racing community for the Formula Ford race spec. No longer a current race spec.
So someone who may have serviced them might have something.
Best of Luck!
Cheers,
Mark
