Sorry for dropping off the map, but work has gotten crazy busy.
Kulas, I am going to build my own. Have a new set (2) of stainless flanges with a shim gasket. 1 for the old stainless wet riser which will have to be cut and welded anyway, the 2nd for the outlet side of the 90% short radius elbow. This way the match perfectly.
I just today was able to get the old flange off the turbo. What a chore after 30 years of use!. 1 nut came off reasonably easy, 1 nut had to be cut with a hacksaw and the last 2 has to use a chisel. Now, need to find the turbo flange. Old one not serviceable nor any part of the assembly. It is square, 4 bolt type, 3" tube and the mounting holes, if measured diagonally (between 2 mounting holes) measure 4 3/4".
What I found curious was the system is made of 3" tube, but the exhaust port on the turbo is quite small. Not able to measure today, but guessing just over 2-1/4" diameter. The steel shim gasket was 3" and the size difference left a large carbon ring between the gaskets 3" diameter and the turbo housing.
If anyone has a lead on the 4 bolt flange, let me know. I have a few emails out to turbo exhaust companies for assistance.