What is your CR and boost if u dont mind sharing. Seems like u mentioned it before but don't remember off hand. I'm facing this same ordeal but will probably run a year NA. I'd really like to stay under 8.5 so I can throw some boost at them to make it worthy.

I figured it to 8.5:1
7.5psi @wot
Dart 345 Iron heads.

EGTs drop 100* with more fuel.
Knock 'noise' goes from 75 to 30 which is low. (at wot)

Do we know the cc of the 1075 head?

Are you intercooled, and what blowers?

Here you go The piston has CH 1.381 witch puts it in the hole .096 on a 10.2 deck block. VP is .064 deep with a caliper. I never measured a 1075 to see if the deck is exactly 10.2 and I don't know the CC of the head. You owe me some beers

Thank you so much!!! What does VP stand for....?

Valve pocket depth is 1/16 of a inch almost nothing.

Pull some boost out and try mid 11s again might save you some fuel and ware and tare and still make the same power. Low 10s the 900s I did would start to misfire on dyno.

10-71 ...non intercooled.

Interesting, the boat did go a little slower at the lower AFR .
How did you know it was misfiring?

I remember in the early days of engine masters they commented about how all the engines were run quite lean and knocking pretty badly. They didn't like it and I don't know if they made rules different.