I would go with 36X13.50X16. Their "E" rated and on an 8" wide wheel they stuff nicley and don't have the balloon/cartoon look to them.
IMHO with 4" lift a 37 will rub. My 36"s tuck and don't rub but theres no more room in the wheel well.
Good luck
AKCRUZERS
Yeah but how much bump stop spacer are you using?