by Tom Calvert originally published in the May 1978 RootesReview
One problem Tiger owners in search of an engine have, is deciding what engine is sitting in that 1965 or early 1966 Ford product. With the engine out of the car, it is not difficult to count the bellhousing bolts. With the engine in the car, it is a different story. One way to tell is to use a 9/16″ socket and a 5/8″ socket. If the 9/16″ socket fits on a bellhousing bolt, the engine is a 5 bolt engine. If the 5/8″ socket fits the bellhousing bolt, the engine is a 6 bolt engine. This method is good unless someone has slipped in an oddball bolt. Check two bolts to be sure. Another way to tell is to measure the distance between the top two bellhousing bolts. The 5 bolt engine measures 5.85″ center to center between the top two bolts and the 6 bolt engine measures 5.1″ center to center between the top two bolts.