The engine was replaced by a 2.5 litre from a 1972 Triumph 2.5PI (less the petrol injection). This was rebuilt by the owner towards the end of 1980, with the help of the machine shop of R. C. Williams of Bachymbyd Garage, Llanrhaeadr near Ruthin, who rebored the cylinders (+0.030″) and reground the crankshaft (+0.010″). This process would involve reboring in 0.010″ stages, finishing to just under +0.030″ by a few thousands of an inch, and finishing by honing (grinding with stones rather than cutters) to precisely +0.030″.
I kept some box labels, as below!