Decoding Engine Block Numbers

[Editor_Reid]

After dropping the oil pan on the "red RHD car" (a BN2) as it is known to its close friends, I noticed these numbers stamped into the bottom of the block:

In case those aren't so readable on your computer monitor, they are:

55
30
69
Z

Just curious if anyone knows what they mean.

Thanks.

 

[Randy Forbes]

I've wondered the same. Somebody should've asked Roger Menadue when he was still around...

Longbridge 2-port engine