Are there any cams available for the 250 that will enhance the 351 kit?
Does the KX use the same head design?

 

There are a few out there. Over here in Japan, we use a Nassert cam, it is a higher lift and longer duration than stock, cost is around $400 for the pair. You can even press the KACR into the exhaust cam. I am not sure about the KX head though. I think web also makes one, but it may be a regrind of your stock cam, not sure.

 

No...

 

Web cams from the US, Jerry from four stroke works might be doing cams, and you can get Yoshimura USA to get D-tracker cams from Japan for you(you'll have to get one of the members from Japan to get you the part numbers)

 

The yoshimura and the nassert are the options from Japan. I may have a set of the Nassert cams available, pending another interested party's reply.

Nassert sale page, the whole kit costs about $1000, and gives you cams, a 315cc kit, and external oil cooler:
http://www.naps-jp.com/php/y-004.php?id=0000134486

Yoshimura cams page, with part number:
http://yoshimura-shop.netmove.co.jp/..._cams3_e&d=300