There were a number of clutch variations available for the 2a including the type of pressure plate and diameter of the drive plate.
I’ve kept the original diagram type pressure plate and fitted a 9.5″ diameter drive plate. These are typically fitted to the 2.25 diesel models. This combination was offered as an optional extra on the petrol models. Standard petrol model had a serviceable pressure plate and a 9″ diameter drive plate.
The 2.25 diesel has less output and logic would dictate a smaller output motor would require a smaller clutch engagement….. but the diesel had more torque (marginally) so the clutch would have to cope with this additional load whilst the gearbox was being engaged when the pedal was lifted.
As the Turner Engineering engine has about 30% more power and increased torque, a larger diameter drive plate is more favourable.