A mk1 Escort will need a check over but mk2 won't need anything as it was standard option, even if the car is pre 77.
A zetec is a relatively quick conversion as it just needs sump and water rail, depending on induction it'll start at 155bhp .
Duratec, starts at around 190bhp and needs the same conversion as zetec done plus a adaptor plate for gearbox option.
Pinto can get a healthy 160,bhp but won't be as reliable as the modern motors or as efficient if that matters, and the cost will be comparable to the later engines Inc engineer, your choice..