Block

After measuring some of the bores with a micrometer and considering the honing marks still present and the cost of replacement pistons around £100 each, I will just have the bores lightly honed and fit new rings with original pistons.         

              Bore measurements were as follows for the first 4 bores (out of time for last 2 )

                               1                     2                     3                     4

Lip                     94.995             94.998             94.998           94.985

Top                    95.015              95.008             95.010           94.992

Middle               95.005             95.005             95.003           94.992

Bottom Stroke  95.000               n/a                   n/a                 n/a

The book size for bore is 95.00mm.

From the measurements taken of the very top of bore and the bottom, the original size seems to be a nats cock under with a very slight taper, 140k miles worth of heating / cooling could account for this. The sizes now are only very slightly over the book specification, again the cost of re-bore + new pistons is not really justified with this amount of wear.