Dan,
You need to figure the compression so you can get the HP you are shooting for. It all has to balance with the rest of the parts you choose for the engine. Building engines is an art not just someone throwing a bunch of parts at something and crossing their fingers to see if it all works together.
The compression needs to work with the cam you pick. The heads need to work with the cam for flow. The valve springs need to work with the cam for lift. The pushrods need to be strong enough for the added load. The timing set need to be strong enough to hold the camand crank timing in sync. The balancer need to be able to handle the extra load and higher RPM. The
oil pump needs to be able to handle the extra flow. The
oil pump drive needs to handle the extra load of the pump and on and on.