Yes to a bigger valve. It’s just the OEM head ports do not flow as well as one would think. The aftermarket solved that. Porting your own iron heads can be a great cost savings and produce excellent flow. The 906/452, etc… very good heads to port. 300 & plus cfm available if it’s done right. Of course there still heavy and it takes time. Money if you can’t port and have to pay the man…. The. I’d consider aluminum. Even more so since I don’t know how to correctly port a head. I gotta a guy…..