Andy, I like that big nut on the end. Should be suitable for turning the engine with a wrench by hand.
Yes, the spline drive setup from Peterson is strong enough that the engine can be rotated with the large nut. The Chevy style mandrels will break if you try to use the center bolt to rotate the engine.
Yea, it is my understanding that the center bolt on those is just to clamp the pullies/spacers together; not to turn the engine to TDC etc. Especially with spark plugs installed !
Do you think the other aluminum mandrels would be OK to turn the engine by hand if one of the spacers was replaced with a big wrench hex with a keyway to the mandrel center? (or like some pulleys have a set screw with sized end to engage the keyway). For example a 1" dia mandrel with a 1-1/2" hex; or a 1.5" dia mandrel with a 2" hex.
