Would probably take at least a day of machine work. There's probably another 4-5 hours getting them off & put back on. Because they are such a finely toleranced fit, everything needs to be pretty much surgically clean when putting them back on.. then you have to carefully torque up all the bolts in a specific order & to a specific tension.manofwood wrote:if a workshop had no customer lineup, how long would it take for them to deck, port and polish, and refit the heads for these? and would the computer need a retune, or would it balance itself out?
Stock ECU would probably compensate to a point, best gains would come with a tuneable ECU.