The originals can fracture, typically this is a hydraulic fracture when oil can't be cleared fast enough (a related issue which we've addressed with additional scavenging), but making them much stronger can't hurt
We need to change the location of the oiling channels and the height of the tappets because we're changing to a smaller base circle on the cams (because we're grinding OEM cams to our new profile)
And we're changing to valves with a longer valve stem to accommodate the changes we've made
Why have we made these?