It's fascinating, Colin, watching this housing come back to life. The steady progression from 'What the hell IS all this stuff?' to 'OK…NOW I see what it's all about!' is incredible.
What puzzles me, is the original design decision to go with an alloy housing in the first place, rather than something cast/machined out of a mild steel. Weight saving jumps to mind straight away, but I wonder just how dramatic a saving there would have been?
It would be interesting to compare your finished case in weight to a best guestimate of what the original case would have weighted just to see what the difference is. It is not uncommon for armour power plants to be referenced with a BHP to Total Vehicle Weight ratio as an indicator of how well they can handle the job. I cannot imagine a weight saving from an alloy case making that much of a difference to engine performance in this instance. Maybe a change in center of gravity of the vehicle was being considered to better the distribution of weight on the suspension system.
In any event, it is great fun watching your progress!
Cheers,
David