Guess we've always just replaced the valve when it comes to impact cases flooding, never gave much thought to the stem kit. Have to check with the local wholesalers and see if they are stocking them. I believe those valves are OEM are the stem kits or are they the same as other sporlan valves? We always refer to the Hussmann valve replacement chart that shows suitable adjustable replacement.
Had an entire lineup of LWU's that were flooding on startup when Impact first came out, Hussmann airmailed the stem kits to install on every valve, since then only seen the occassional impact valve do the same.