Transmission Assembly

We encountered our first real assembly problem - aligning the bellhousing to ensure concentricity the clutch / crankshaft assembly and the gearbox input shaft. The first picture shows the way this is measured.
The D Type Service Handbook gives clear guidance on the acceptable limits and advises that if the assembly falls outside the limits, then "a new clutch housing must be obtained and fitted" - easier said than done 50 years after the event!

Our problem was that the location of the dowel holes on the block did not match the dowel locations on the bellhousing. On checking the drawings and after careful measurement, we found that it was the re-maching of the block that was in error - by about 0.50mm.
We rectified this by making a laser cut jig - see second picture - and redrilling the misaligned dowel hole in the block - phew, it worked!