Paul, that's exactly what I'd do (and more or less did). Anything you can do at the moment to make your build simpler will get you on the road quicker, and you'd be suprised at how little power a car like these need to be fast and fun :)

Probably the best RWD Zetec resource on the 'net is http://www.zetec-cat.co.uk/ it concentrates on the later "Blacktop" engine, but most of the info is relevant. It even gives you the part numbers of any bits you need.

My car passed the SVA with an old 1.3 crossflow on a Motorcraft carb and was sooooo much fun, it also qualified the car to be tested to "visible smoke" emissions levels for the life of the vehicle.
After rebuilding and then wearing out a 1.6 we eventually bit the bullet and bought a £50 Zetec [1] and managed to shoehorn that in (the locost has an even smaller engine bay than the roadster). This means that it could be running miles out (and is, a bit rich) but it doesn't matter for the MOT :)

Also, if you build your perfect car first time, what are you gonna do during Winter ? :)

[1] Got lucky here, got a new water pump (the Escort version), starter, CVH sump, EDIS, spare head and loads of other bits and bobs thrown in.

....I should probably get on with putting my bike back together actually lol...

sounds brilliant @ build book design then swap for zetec. Thanks for all the advice/info :)

welder should be with me next week, a few people have recommended rufforth autojumble (which I didn't even know was there) for some metal offcuts for practice etc, when I'm happy with my welding I'll get the flatpack kit from armoto, plates from 3ge and away we go :)