To preload the top of all the cylinder walls correctly you need to use the same type fasteners as will hold the heads on as well as have the same thread engagement in the block bolt holes up scope
I have spacers for the five center head bolts to simulate the same loading as the motor will have with head bolts or studs for my steel BHJ honing plate.

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)