Today's update:
Finally! It lives again. Took a while longer than I had hoped. I don't think I've tried as hard to have everything done right working on an engine and had as many issues arise as they did, but its all done now and running great. The Powermax has some nice top end, seems slower to spool than stock but its been a long time since I drove with the stock turbo. Running a CTS with EGT and fuel pressure sensor. I did not take that many pictures besides this piece that I made with some description about it.
On the left in the picture below is a piece of rubber that helped the support the HPOP branch tube. It was fastened in the back of the block. At 203k it seemed to be deteriorating. I could not find this at a Ford dealer, even looking at the parts diagrams with partsman. Seemed to be serviceable only with the branch tube replacement. On the right is my first rendition, a piece of plastic machined in a lathe to be a press fit. After thinking about engine temps I decided against it. Had I not forgotten to order the back plate o-ring seal, I may have installed it.
Here is my second rendition. A piece of aluminum, once again machined in a lathe, with grooves cut for o-rings. This was a piece I made myself. I saw no 'outward' support for the branch tube from the original piece, so I saw no need to make any provisions either.
I did replace the HPOP discharge tube, so the only o-rings that weren't replaced in the HPO system were the stainless hose pieces under the valve cover. So far so good. Only 365 miles on it. Last tank of 230ish miles of varied speeds for break-in I still pulled 16.7mpg.
Next mods, engine oil bypass(I tapped a hole in the upper oil pan for a return) or replace some idlers as preventative maintenance on the front of the enigne.... there are a lot... dual alternators. Maybe some videos to come of driving.