Been there and done it too - Stage 2 MGB motor in a Wolseley 1500. I used to run this engine in my Minor after my full race one went bang. It gave exactly the same performance in my Minor as my mates 2 litre Fiat. As we all know, the woseley is based on a Minor, but is uprated to take the heavier engine. As a relatively cheap swap, I'd use an MGB engine and O/D box, coupled to a better rear axle (you will break diffs and halfshafts) - Ford or even MGB. You'll also need to upgrade the brakes as the weedy drums will fade dramatically if you like to press on.
I wouldn't bother too much to go Fiat - getting old and expensive to get bits for. If you want to go modern, zetec seems to be the way forward - or thinking out of the box - a modern turbo diesel.
Good luck whatever your decision.
Incidentally, don't bother with an A series - was never outperformed by one in my MGB engined Minor.
Pete
I wouldn't bother too much to go Fiat - getting old and expensive to get bits for. If you want to go modern, zetec seems to be the way forward - or thinking out of the box - a modern turbo diesel.
Good luck whatever your decision.
Incidentally, don't bother with an A series - was never outperformed by one in my MGB engined Minor.
Pete