some machine shops like to get the parts they like to use BUT saying that they maybe would want you to get them on something this old? on the head work they are not that much diferent than any old iron heads they will need hardend seats on the ex side and on them chip guides do not worry to much on that i use a manganese bronze guides that od is .502 so this will fixs them up so the seal will work on them and a good 3 angle valve job and some ss valves .who ever works on your heads i would make sure you get the same heads back you do not want some heads that are beat to hell and the bottom end would be a good place to spend your money this will have alot to do with how much boost