Kohler San Raphael ball cock valve replacement

HI - I have a broken valve in my Kohler San Raphael - imagine my surprise that Kohler wants $110.00 for a replacement kit!
I came across one plumbing site that said a Coast Foundry 1B1X could be a replacement with somew work, any idea what they mean by "some work"? Any other replacement ideas would be welcome.

Thanks

Bob