I wish I still had one, I would offer it to you. But, from what I understand the H72 (low-comp GX head) would be a good high-flow turbo head. As it is low-comp to start, and with a head gasket shim, I think it would do very well. I got the ones I had from 1978 B210 GX cars, so you maybe able to find one if you look hard. I was able to auction them off for US$120 each (one was sold to Australia).

There is a short section in the heads tech section on this head.

I'm building an A12 that I want to turbo. I was just curious about the best head to use-A15, A14, or A12 and what are the benifits or disadvantages of each. Any help would be appreciated. Thanks