Thanks Frank, I have SGT seats as you said very like yours, and sitting in a dropped floor pan, but no "bulb" which sounds good. Nice to know I am now certified normal.Nick, yes, but that's customer preference. I usually fit the flat bottom of the seat directly onto a lowered floor 40mm below normal floor level ( no runners ) gives the perfect ride height for " normal " people,
Looks like an original GT40, or maybe a perfect copy like the Gelscoe cars (or other faithful, exact copies). The seats aren't seats in the conventional sense - the bases are webbing straps which are stretched between welded-in mounting strips:-
The seat backs are glass-reinforced epoxy resin - GRP or fibreglass - which are separate, and retained to the firewall (by Dzus on the original cars, I think?).
@shaunybean on here has re-created them for his build. Pic above is another Gelscoe car, for no other reason than there are plenty of good pics on their website. @brianstewart re-created a pair for his CCD-chassis build; see on the Build Logs on this forum, and on Pistonheads:-
The upholstery is some form of fire-retardant nylon with minimal padding and the all-important eyelets.
What are you building?