Was yours a diesel? IIRC, that was the difference.
Although, there was much shared then. Is it possible you and your Dad had the same motor, with different heads?
(Sidenote) My 1993 Ranger was sold as a Mazda, but in that case it was Mazda selling a Ford product, not the other way around.
It wasn’t a diesel but it is entirely possible they were the same engine with different heads.