Doesn't the H signify the holder uses a different screw to CCMT and CCGT? might get away with it, might crack the insert.
Its probably a bit of a special insert or at least coating to deal with the high silicon content maybe crystaline diamond coated as I have read of another high performance model engine builder who uses that coating to machine his 30% silicon alloy pistons
Edited By JasonB on 01/01/2016 20:34:05