I have to agree with Twisted and efi-diy that getting a run of new aluminum heads made is not for anyone wanting to make money. There simply would not be enough volume. I know the Riley arguement has been brought up, but it is much easier to cast and machine than the late inline head. Also, for many Inliner's, partly out of necessity find their own way to do things and not spend the big bucks to get a job done.
There have been a lot of technological improvements in the ~45 years since the late motors were designed,but without going to a cross flow head, what will the average (not hardcore super funded racer) gain going to a new aluminum casting? Other than some weight savings and a cool factor for the few who will know the difference, will there be as significant advantage over a stock head that is done by a knowledgeable and talented engine builder?
