I recently acquired a 68 Lincoln motor for my 87 f250. After some research I realized this set up wouldn't be good for its intended use of towing on today's gas without machine work. So I'm now looking for a set of D3ve heads to replace my c8ve heads. My question is what are my heads worth? Would it be smart to try and trade for a set or sell mine and buy d3's. what is a fair price for both types.