Ed - people tend to use the 8 valve Twin Spark from the rear wheel drive 75 for this conversion. It's lighter (all alloy), stronger (chain driven cams) and easily modified (190 bhp on throttle bodies and mappable ignition). Plus it's already come from a rear wheel drive chassis and conversion parts are readily available from people like EB Spares.
That's all right, but the reason a 155 lump was suggested was that only the 3 litre 75 (Milano in the US), was available.
The answer is yes (to the 2 valve head), but be prepared for some difficulty with interference with the plenum chamber around the bulkhead fittings. Alternatively, as already suggested, use a mapable throttle body system and get the sound as well!
I really don't know about the 16 valve engine, and as far as I know, then you are in uncharted territory.
That said, I take it you've already reserched the matter?