IF THE SKY IS THE LIMIT BUY SOME GOOD HEADS. By the time you fix up old stock heads you will be half way to a good set.
14-15 TO 1 COMPRESSION, SOLID ROLLER AROUND .750 LIFT WITH dur @.050 270-280 range 112-114 LSA VICTOR 454-R
JMO although I would probably ask an engine builder. Use the rectangular port heads.