That 38* of timing would scare the crap out of me without an egt gauge. You might wanna check them plugs at minimum , Id be afraid those exhaust valves are getting toasted.
What it wants on the dyno for a 10 second pull doesn`t really tell you what it likes on the water.
BTW good job F-2 Sleepy, you called it not a 1.50 drive

I've got about 40 hours since the engine builds. I've checked plugs a few times along the way. Plugs have a clean burn, light tan/brown on insulator, but get sooty after a long idle.