Most of the stock heads Ive seen are between the high .400s to .500 max,it really depends alot on the valve job ect.In this case it seems a cam change would provide alot more power than a increase in lift-the lunati braket master is a pos for .006 vs. .050 and I had the unfortuante experince of seeing how badly they stacked up lol.My machinist has never really seen big gains in stock heads from over .500 lift cams but more duration works to provide more area under the curve so to speak.But now with serdi type/multi angle valve grinds ect.,it nice to have modern higher lift cams for the duration,my heads have a 50 degree seat and the transitions incredible.