All depend on what power your looking for and wether your gonna turbo it..
If you turbo it
You will need new pistons but standard rods are good 270 bhp fit arp big end bolts for extra strength. some oil ways will need to be blocked in the block but a proper zvh head gasket will do the job fine. If the head you have got is not of an escort or fiesta turbo one you may need to change the valves as a norminally asperated head doesn't have sodium filled valves. the block will need the oil breather under the exhaust blocked and re located on the back of the block as the turbo gets in the way. there is a few more bits that need to be done if you need more help pm me and i'll give some links to some helpful sites.
If your not gonna turbo it put the 16v head on it forget the cvh head bolt on some twin 45 and happy days your away no need to modify any thing just make sure the engine is sound.