i have a raptor 660 and it has a big gun evo, hot cams ,rev box , air filter , and is in the shop right now getting a 690 kit. i was wondering if i should get a longer swing arm and if so how long? and i ride the dunes.

 

Yes you need one.

I run a 4" arm on my 700 to keep the front end down with my Skat Trak Haulers. IT works well, and handles great. I feel +2" would be a waste, and +6" would detract from handling and wheelying ability(if I wanted to). I can still pull wheelies with the arm, but it takes effort.