Mk1 Escort Specifications

[rfl]

Looking into the possibility of buying a Mk1 Escort for racing in Top Hat Groovy Baby series and eventually in one or two FIA events.

Can anyone provide info/ a steer to websites that detail the period specifications and background to these cars- either twin cam or BDA engined (Group 1/ Group 2 regs?) as I ultimately want the car to be FIA compliant.

Thanks