I feel the Indy dual plane is a very good dual plane. I have it in the standard port form (just port matched to stealth heads). It’s on a pump gas 505 RB and made good power on the dyno and ran pretty good at the track. I just lowered the plenum center divider and radiused the upper transition. It made 600+ hp on dyno and ran 11.55 at 4200+ lbs. i’m very happy with it’s performance.