Center side mounts started in 1952 in cars and stopped in 1954(for 4 years)but were never used in trucks(the truck engines had the bosses for side mounts but were not used).
Front side mounts were used in 1955-57 cars and 1955(2nd)-59 trucks(there was no provision for center side mounts on these engines).
1958 engines saw a new upside down bolt pattern center side mount, but again, only used in cars.
Except for 1955(2nd)-59, trucks were always mounted on the timing plate
1958-59 engines are the only engines to have provisions for both center and front side mounts.


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