Curious which cams you are looking at? And do you have any other work done to it?
I have a couple of these motors in flat track frames that run pretty good, and definitely cams can make a big difference. I may have some of these for sale cheap, if you're interested:
Kawasaki EX650 Racing Camshafts Hard Weld: Spears Racing camshafts are developed through countless hours in the dyno room, racetrack
spearsenterprises.com
They made decent power, but it was mostly from mid range on up. So I put the stock cams back in this particular motor (It's my short track motor and I just wanted smooth, useable, power and can definitely give some up on top.) Not sure if I want to keep them for a spare set for my 5/8 mile and up motor or not.
I'm sorry I can't tell you for certain how much power you'll gain, as it seems to depend on matching the cams to the head and exhaust combo. I can tell you in my 700 motor, with an S&S exhaust, and Spear Racing headwork, the bike made 86hp. My stock 650 made 64, so it was a noticeable improvement. I just can't tell you exactly how much came from the head, or the 3mm oversize pistons and cams.
If they're something you're def interested in, make me an offer that is worth it for you to try? Would probably just need to degree them in, set the valve lash, and go. These particular ones are advertised as using stock springs, and that's what I had in my 700 motor.
