Kernow

Hi I am new to group. Learnt to drive in a 1964 mk1 consul cortina. Had a couple more after that. Have decided to look for a mk1 cortina gt l have seen a few advertised some of them are from South Africa. Does anyone know how to decode the vin plate to check if it is a genuine gt. Also some SA cars have cross flow engines fitted. Is this a factory fit or are they replacement engines.