You can run dyno oil up to 230* no problem. If you get your cooling system up to that for any length of time, the engine is probably on it's way to a melt-down already.
I've been cooking my oil in the filter for over 100,000 miles, and it hasn't seemed to be a problem.
I run a shorty, no 90*adapter, and TTIs; but I also run dual full-length 3" pipes,without a cross-over, to get rid of that heat..