Voith

Testing was done when hardware was available imo. Maybe it's some personal head from someone that had influence in porsche and had himself a nice sonderwunsch 3.0T.

RajDatta

Thom seems to have it right. Definitely not a factory production turbo S head. Looks like a hybrid. As Thom stated, probably a prototype head used by the factory. I have heard of such heads as well.
The question becomes, what is it worth when it's neither the Uber rare Turbo S head nor the more readily available 2.7 head. Seems more inline with a 2.7 head modified for turbo application.

Voith

It must suck if ceramic cracks on head as rare as this.

333pg333

So how many 8v heads did the factory make? Just reiterates to me what a shame it is that they didn't put as much time and money into a production 16v turbo head...

RajDatta

It was much easier to use the parts bin to build a fast 968 turbo without entering 3.6 turbo territory. Keep in mind, a 968 could not be faster than a 911. A two valve gave them enough. Also, at that time, porsche did not have any production turbo charged engines with 4 valve per cylinder.

V2Rocket

Have heard the "can't beat a 911" comment before but hadn't considered the technology gap...

Up through '94 the 911 turbo still had hemi-head and mechanical fuel injection...

So a 4-valve turbo 968 would surely steal the thunder...