The catalog I imaged has extensive conversion parts specifications and both the L-71's and L-72's are cataloged by GM PN#.
So the car being discussed started life as a SB potentially? It should have started life as an L-78.
If it started life as a SB:
Motion sourced a correct 4.56 geared rear end assembly.
Did a BB heater conversion to the firewall
Built a spec L-72 block to Motion engine specifications using a donor engine
Added an Aluminum Blow proof clutch package to the build
Used the typical ignition system and Sun Tach
Used the Motion glass hood with no other cosmetics.
Used a FLY-EYE air cleaner
Used the Offenhauser style finned valve covers with the Motion plaques that later came into the full catalog line about 24 months later in 1970.
Small blocks had finned valve covers already in 1968 but they were the pre cast "Edelbrock" aftermarket kind.
If it started life as an L-78:
Built a spec L-72 block to Motion engine specifications using a donor engine
Added an Aluminum Blow proof clutch package to the build
Used the typical ignition system and Sun Tach
Used the Motion glass hood with no other cosmetics.
Used a FLY-EYE air cleaner
Used the Offenhauser style finned valve covers with the Motion plaques that later came into the full catalog line about 24 months later in 1970.
The catalog does state in the how to build section that "Any L-72 or L-71 with 4 bolt mains can be upgraded for maximum performance service using components from the heavy duty parts list" and Joel introduces the reader to the art of converting the lower end of these motors into what was called a complete "Stroker lower end" treating each engine as a unique and individual project.
With that said there is zero mention of Motion offering any in house substitution package using parts previously installed from another vehicle associated with a new car sale through Baldwin.
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