I'm going to assume that your clutch and bearings are in good shape, and that you have no air leaks. That being said,I never tune to temps, anytime I used my temp gun while I was trying to tune any engine, I had tuning nightmares. 230-250˚F is where I like to run my engines. I don't like to run my engines cooler than 220˚, or hotter than 270˚. So your temps are fine.

But seriously, I don't even take my temp gun to the track anymore, it stays in my shop, and I mainly use it for breaking in a new engine.

It sounds like your LSN is a tad rich to me..if your loading up and stalling after a minute. Does it make a blubbering sound before it stalls ? Then it's rich. Does it idle down fast after WOT run? I know that the idle on this mill can be finicky at times, but generally, it runs great.