http://www.retro-ford.co.uk/shop/
These guys also supply kits for zetec/ duratec into Escort. They even do a BDA style rocker cover for a more period look.
Can be costly but you cab fab the parts yourself, lookout for import duties too. The kit will cost about the same as building a hot Pinto but once you have the bits the engines are a dime a dozen and you just swap them over in case of failure.