yes a zetec can make 500 brake, do a google for area 6. you don't need 30k thats just silly. for 300 brake you may as well use the whole st170 engine, after all its just a zetec with better components and a better conrod ratio.

few items that will be needed on your spec list:

area 6 or equivalent intake manifold
gt35 etc
aftermarket management
custom cams
forged pistons
forged h section rods
not sure on crank?

Rob,