You would be better with a 66 and newer 273 head, a early 318 head, or a #302 head from a Late 80's Lean Burn. They are all closed chambers with 318 sized ports. 340 heads are open with a large chamber which is a loss of compression. Unless you build a real hot rod engine with power in the 5-7000 rom range, the large ports of the 340 heads won't help you much. What is your plan? Just a head swap or a zero deck rebuild?
