I was reading in another thread that the /6 head was originally designed for the 170c.i. version. Also that its difficult to put decent sized valves in the head because of the small bore size of these engines.
So keeping in mind we are stock with a factory type head that was designed for 170c.i. and are limited to valve size. Lets port the head, put the biggest valves in we can, and put a turbo on the engine.
So for maximum horsepower, what size engine would be the best? Would the smaller 170 be the best since the head was originally designed for it, or does the old saying still hold true even with a turbo and small head "no replacement for displacement" and go with the 225? Or the 198 that falls in the middle?
