Whew had me stumped w/o Jim's remark. I only really know Combats, still filling in on other lessor versions. Combat had head trimmed thinner so push rods should of been shortened by factory to improve rocker geometry - so it left to us to finish the kits Norton started. One size fits all from factory but you know how that works out when seeking best fit. Change a gasket or base plate - same thing- its now a special!