The #94's will have the small intake valve so I would go with the 6X but don't get rid of the 94's. You can install larger intake valves down the road if you want to use them and I think the CC volume on either head will be similar. I think the 6X is better but doubt you would notice the difference between the two with both having the 2.11" intake valve.
http://www.wallaceracing.com/head1.htm