Many thanks to user 97 SL320, the unicorn manifold has been found, pulled, and shipped. It came today so prep began for its installation in the near future.

As you can see in the first pic there is a very rough casting flash between the 1-2 and 2-3 runners. Given that this is where the current manifold is cracked the first step was to grind out the flashing hopefully eliminating a point where a crack can start. It isn't exquisitely detailed, just rounded and smoothed in the corner.

The next step was checking the flange for flatness. It could stand some significant improvement so I spent about an hour between a flat file, 12" disc grinder and a sandpaper flat plane. I went from 0.017" warpage down to 0.005". I'd like to have perfect but ended up chasing it and determined that 0.005" was as good as I can get it.

After bead blasting the remaining sealing surfaces, I traced the T3 gasket onto the manifold. My every instinct says port match that sucker because there is a fair bit meat in the way. My inner coward is afraid of releasing some internal stresses removing that much material opening the door to cracks in this otherwise perfect piece. I think I'll wait until I unbolt the turbo to see how this gasket lines up on the turbo before grinding anything.

Attached Thumbnails

       

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90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff