I ran pump gas up to 150 a shot, and 180+ I used 50/50 (v/v) pump/race gas as added insurance (along with 28 degrees timing). Anything to keep detonation at bay I thought was a good thing. The motor ran N20 99% of the time for 7 years with no problems.
I know people run nitrous motors on pump gas only...but I wouldn't unless you're running a small shot. Just my $0.02.