RB25NEO kelford valve springs

[Antonio2111111]

Hey guys,
I've got an RB25detNEO that I'm building. I got a set of kelford valve springs. The problem I'm having is that the machine shop is telling me that they can't properly adjust the valve lash, because the kelford springs on the exhaust side are too tall. Not that there's a binding issue, just can't set the valve lash.
They're saying that I need to get RB26 buckets.
Has anyone seen this problem before?
Thanks for the help!

[macgiver]

A reason why other than binding on the way down , which would'nt have the detrimental effect so related to lash as the "closed spring tension" and @ height of said spec - is not kosher to setting lash spec . ie. closed they sit too tall or too remotely possible supplied retainers achieve out of spec height and similarly not in the ballpark for std. adjustment procedures . Inferring that geometry -" can't get there from here ".
I know that's not a solution , but be wary of tips that "can MAKE it work" , get second opinion , hopefully someone has real experience here specific knowledge , beaucoup "builders" on this site , ya know. And tapping another mach shop w/exp on that motor and /or Kelford specifically most valuable too ,see what they say.

[AntonioG]

I know this is old stuff now, and my project is still going on(everything being on back order and such), but just thought I'd update this if anyone was interested: that shop just had no idea what they were doing. The springs went in fine and the valve lash was set just fine as well. No change in buckets or anything like that.