James, maybe get the good guys at Ruf GB in Weighbridge to look at and drive the car. They know more about what is appropriate revs and load for the car than the seller does. And can treat the car in such a way that it answers your questions while accommodating the seller’s reservations. Also, if the chap has done the restoration himself there may be a lot of things amateurishly done that Ruf GB will point out. Tell them Bill Douglas in New Zealand sent you along
