Here is a great site to look up fork info for putting newwer stuff on an older bike.
http://www.tech-care.com/I knew the 2008 rmz250 forks fit on my build since I tried it out.
I looked up forks and tests on the site. then looked up tests of the bikes focusing on the forks.
Picked 2006 rmz450 front end based on spring rates, fit, condition, and price on ebay.
The 2006 uses basicaly the same 47mm twin chamber showa set up that is on my 2008 rmz250.
I wish I knew if sss forks would work. that would have cost a bit more.