John, sorry to hear of your loss. As we get older "life is short" comes up more and more often.
Hate to see you bailing on the H6, but at any platform has limits (how much power were you making?). I echo your success with stock engines, but when you get pulled down the straight, it's easy to think about more.
Racing is really hard on the equipment! I remember formula ford used to be 20 hours on a crank, and anything after 18 was gambling. I lost a couple of those bets... Fortunately, they've finally figured out the 60's tech, they last longer, and I'm going back vintage FF racing! But... the cost of a Loyning or Ivey pinto engine makes eyes water.
My street/stock H6 is still running well at >5k miles, and but for an oil leak at the head/case no complaints.
Any thoughts on your next platform?