Bodi

Can I run a hotter heat range plug in my 525SC than what is recommended by Mercury (at sea level I assume)? I think the motor pulls 5.5lbs of boost at sealevel but at 4,900' in Utah I am only getting a little over 4lbs. I keep fouling my plugs at 6,200' (Flaming Gorge). I was thinking of going 1 heat range hotter because 2 heat ranges would put me at the stock heat range plug for a 454 Magnum.