I still think that if you are going to stick two head hunks together to make one a good bet would be two hunks of 181 Mercruiser heads. It would make a 12 port, though not cross flow. All the holes would be in the right place and they have big valves stock. They make 140 HP on a 4 banger stock. Valve placement would be the same as the 6 and valve train is the some. Probably not as good as the traditional hybrid but so much easier.
