Yeah those arps are high but worth it to me I heard that ats h11 are about the same except for resistance to water/coolant that's why I went arp 625s now on the groove I'm guessing you mean 40 thousandths .040 that's a pretty deep grove how are they fixing it if you don't mind me asking

 

your right i meant.0040, and they're going to deck the head about 50 thousandths, the fractures in th head are all in places that they cant affect operation of the engine or this is what i'm told.
Enterprise Engine Performance
they seem to know their stuff so i trust em, and if they're wrong