If you're dead set on the idea, honestly, I'd just have a bare housing made and be done with it. There'd be a higher initial cost, but it'd be absolutely worth it in my book.
I agree with this. I bought an '85 HP 60 for mine and needed to re-center the differential to get my front drive line straight, so I paid up and had the tube swapped and Reid Cs put on at the same time. With the cost of the work I wish I had simply had a custom housing built, I would have been a little bit of money and a lot of time ahead.