all the heads can be used they all interchange.
For Improved Flow Good valve job (3-4angle) Clean up the ports. Bigger valve (depending on the Need or Plains for the motor) Boss removal can gain some CFMs. ADDing a bolt-in Lump Well also Greatly Improve The CFMs. And To the exstream side of things Rasing The Ports have Vast gains to the CFMs as well. But Is FAR MORE Costly.