Maserati A6 GCS from about 1953
The original engine was a 2 litre 6-cylinder Maserati engine similar to the one in the Fotmula 2 car. If this has had an engine swap then presumably it's Detroit iron - a Chevrolet V8.
And judging from the skirt length, I would say this photo dates from 1968
Well you are definitely on the right lines here.
The car originally fitted with a Maserati engine. However it was replaced by a British engine as shown in the photo.
As a clue - the base car is British notwithstanding the Maserati style radiator.
You could be right about the photo dating from 1968 (yes I remember skirt lengths in those days very well!) but the car dates from much earlier of course.
I'm going to
LOCK it for you in case you have any more thoughts....