Be careful, as the engine management, abs, stability and traction control are all linked. You would be better going for an aftermarket ecu, an emerald, or similar. Also remember, for mot purpose, you'll need to retain the catalysts. When engine swapping, emissions go off the age of the engine.......
This is not quite correct Bruce. For MOT purposes, when the car and engine are not of the same vintage, you may elect to have the car tested to either standard, however, default is the standard for the oldest component (usually the body) since the age of the engine is not easily proveable.
I ran into this when MOTing the Carledo and was asked how I wanted it tested! mostly I just go for the pre 75 "visible smoke check" but once - for the craic - had it tested to the standard for the engine which, being from an 89 car, was not a cat test so it passed with flying colours. In fact it has all the cat equipment except the cat itself and when stinking hot, comes within a whisker of cat test standards, HC and Lambda are within limits and the the CO is only about .5 (limit is .3)
It is possible to put a 50s V8 in a modern shell and have it "visual smoke check only" rather than the cat test it should have......But I don't know anyone who has tested this theory in practice, though I came within shouting distance of buying an 80s BMW 3 series with a 60s SBC fitted!