mark maras kindly provided a donor balance tube for me to strip down and clean up. i decided to re-locate the brake booster to the firewall end of the log and save one vacuum tap at the front top and keep the pcv at the center horizontal position.
started off with a sawzall and hacked off the big lumps, then angle grinder with cutoff wheel to bring it down to rough shape, then a flap wheel to smooth it out, hand file to blend contours, 100 grit up to 320 hand sanding, scotchbrite then a bit of buffing. next i'll weld in the deleted holes, grind those down to match and she should be done.
not show-quality work, but i'm happy with the improvement.
starting point:
cut, ground, filed:
buffed: