Valve choices

You can buy 7MM valve stem blanks from SI and create your own custom valve if you have the capability. I've done it for several V engines before. The 7MM stem really improves flow by reducing the valves footprint in the bowl area. That coupled with a reduced diameter and shaped guide gives you almost as much gain in flow as a mild ported head without having to mildly port it. Just imagine if you ported the head and swapped to the 7MM valve. You likely exceed the flow of a radically ported head with only mild porting....I'm sure other companies sell blanks as well....