Engine Numbers

[PVANDAL@aol.com]

The parts catalogs I have describe engine parts by  commission number of the
vehicle.   My '68 TR 250 does not have the original engine nor does my '71 TR
6 bone car (I assume).  I would like to at least date the engines so the
proper replacement parts can be acquired, is there a cross reference printed?
  The two engines I have are numbered "CC/31782HE and KD/52235E".   My BMIHT
certificate lists the original engine as CC/4228-E in the TR250.
thanx in advance