Be sure to run a thread chaser down all the bolt holes before replacing the heads, if any of your ARP bolts are damaged from rust or corrosion, ARP will sell individual bolts verses a whole set. Also a couple drops of motor oil under the bolt head, or around the bolt holes on the head itself will give accurate torque wrench readings. Be sure to go in proper sequence, and in a 3 or 4 step pull to final torque. Fel-Pro makes a teflon lined, composition gasket for W motors that I have had good results with. Note there is a difference between a thread tap and a thread chaser, one cuts, the other one cleans.