If you have retained the HYDRA-MATIC, the RG is on the flywheel.
If you turn the CS while priming the oiling system, it may wipe the assembly/break-in lube off the cam and lifters.
* Along with if the fuel is not primed or ignition lead not set correctly to allow fast start, extended cranking will wipe the cam assembly lubricant or if the oiling system is not primed will have a dry cranking period on hard start.
I would do all of this after the engine/trans is mounted in the car. Unless you have a break-in stand, starting one on an engine stand might prove disastrous (IMO of course).
Don't forget the blended break-in oil (no additives).
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