Ant,
I originally did the same with Ally plate and had bosses onto the timing cover, but that was when I had a Meziere pump with twin outlets. Unfortunately one of their employees 'never received it' when I sent it back for reconditioning so I was left with just the housing. So I have now opted for a Davies Craig unit. I know a lot of people have debated the pluses and minuses of said unit, but that is what I have. Unfortunately, it only as it has only a single outlet/inlet, I have to find a way to mix the water from either side of the block in a neficient way, and I thought why not use an old water pump with the impellor removed and welded up. Personally, I'd like to try an ally one; whilst I have an original cast iron pump, it still weighs a bit. Thanks for the pffers all. I'll follow-up.
Brett