You could use an ST170 motor on motorbike throttle bodies and get a very cheap, quick old motor, and I beleive with a vernier pulley on the exhaust cam a few more ponies can be extracted.

Dave Colledge at Retro Ford has one fitted to his MkII Escort development car and one of his customers has one in an Anglia (www.retro-ford.co.uk)


As for emissions, talk to Troy at Northampton Motorsport, they have a customer who converted his Focus to run on Throttle Bodies and weber management and as far as I know it can all be mapped to be MOT friendly.
(www.northamptonmotorsport.com)

Hope that helps