Its not a definate decision, but if anyone is interested it would make my decision.. I have a pair of GMPP Lt4 heads with minor port work.. They have had the bowls cleaned, port match intake and exhaust, clean around guide bosses, 3 angle valve job, valve inlet RA and polished intake and exhaust ports.. Since that work they have had 8,000 miles on them, also they have Comp Cams 987 Double Valve springs good for .600 lift.. I have had no problems, still on the car, decided to go a different route.. I paid $1460 out the door from Summit, plus $750 in porting.. Im asking $1700, but open to offers..