The engine in my car uses a carburettor. It is the B230K. Unless you want to convert your engine for fun, it would probably be easier to drop in a B230K engine. The B230K was given a Pierburg 2B5 or 2B7 carburettor, although in the UK it is common to convert these carbs to the Weber DMTR when the pierburg gets old and dirty inside. Volvo also produced a 2 litre engine that used a carburettor. These were the B200K, which aren't as good as the B230K.

To answer your first question, all 740s have a computer of some sort. Even carbed Volvo's do.
I think the distributor is wired straight into the ECU.

In my opinion, the B230K was the best engine for the 740s in terms of fuel economy, reliablity and longevity. The only drawback with these engines is that they are very slow to accelerate.

Cheers
Will