Cheers mate. Do you mind my asking cam, rocker ratio and rpm specs? Just curious. A bit of real-world data always helps.
Had to laugh at your TF heads – what on earth were you doing swapping out those "premium" springs for lowly beehives? Unless you bought bare heads. :p
I see Lunati recommends that spring on nearly all their HR and SFT cams for SBM – some of which are rated for 7500+rpm. The alternative dual spring with damper (73195) has 402lb rate compared to 280lb for the beehives. That's a big difference.