Do you have the cases split? A 650 exhaust cam will make a noticeable difference.
My go to cam timing is around 101 degree lobe center intake and 105 degree exhaust. Seems to make good power where needed most. Unless you check, you will not know what you have. Just moving gears around could be an exercise in frustration.
Most 650 ex cams I've checked clock in at about 98 degrees stock marks. Most 750 ex cams are more like 92. Either would benefit from moving to 105 more or less in my opinion.
My 650 desert sled was assembled on the stock cam marks. Put down a whopping 29 hp. Ex cam was 98*. Moving it to 104 saw an increase to 34 hp on the same dyno. The power is in there somewhere, you just have to find it