Thanks for the replys so far lads.
A few more questions seems you're all so helpfull

So a .48 housing is good for low in the rev range power, but isnt good for more than 370Hp, but is good for beating the jappas off at the lights?

A .55 housing has good mid rev-range power?

And a .63 has high rev range power, or does it only give you an increase in "top speed"?.
With my setup ( which I list in my first post here) if I did get a T34 what is a rough estimate of how much power I will have, will it be more than 370Hp thus making a .48 housing a waste of time with my current mods?

Also as I'm reletively new to the whole Cosworth scene can someone explain how you launch succesfully and what is invovled with revs, where your feet are placed on the pedals etc, Im sure launching is real bad for your car though right?.

Thanks again guys, you're all a world of knowledge