360 head on 318

if it were me I would either get a good flatop piston or shave the heads to get good comp. If you shave the head you must also shave the intake. Get new 360 head and intake gaskets and a;lso a 360 intake. It is a good plan due to the bigger valve on the 360 heads. If you got to Kieth Black piastons website they have a comp calculator. Also if I were you I would get a head gasket that is the closest possible to your bore size so not to lower your comp. http://kb-silvolite.com/calc.php