tough 1 lad did u try look up the http://www.kaklub.co.uk/ theres alot of conversions on the with rst and 2.0rs engines.
Track Designs site lists all the engines you can use their mounts with - very clear info.

Our Engine Mount Kit Allows the following engines to be fitted to a KA:
•Zetec 1.8 silvertop
•Zetec 2.0 silvertop
•Zetec 1.8 blacktop
•Zetec 2.0 blacktop
•1600 CVH
•RS Turbo CVH
•ZVH o Zetec Turbo
•Focus ST170
•Focus RS Duratec

dunno could you use the ka gearbox though itd be the job if you could