80 mm ? are you sure of that, maybe we are talking about different things? 80 mm? do you mean the removable plywood lid over the back axle etc? mine is a 2 seater and behind the seats is a plywood cover. Is that what you refer to as the "cover board"?
my springs are 5 leaves BTW
Peter
Yes Peter, that is what I referred to. I measured it yesterday just for you with nobody in the car and a nearly empty petrol tank.
If you already have 5 leaves I wonder if they are "original". I know cars of the early seventies with 4 leaves like my 1967 model. I changed from 4 to 5 after the first set of springs had sagged to a degree that in fast driven bends the tires touched the sharp edge of the steel strip inside the rear wings and showed deep cutting marks in the side wall - scary!
Frank