286 cam and 1.5 roller rockers

[cav773]

Hi way back in 2012 I raised a query about using 1.5 rollers with an MD286cam. I did and everything was fine. Recently tried the same setup on an A-plus engine and am getting valve Spring bottoming out. Is there a valve Spring solution or shall I go straight to 2mm rocker pedestal shims or something I really don't want to do, get rid of the roller rockers . It maybe the head has been over machined (have no history on head) . Thoughts please would be greatly appreciated. Thanks