what does this mean?

What engine..where on the engine? What car?

Cheers

looking front on, its on the right hand side, below the mount and further to the rear of the engine than the mount, either an A12 or A15, i want to know where the engine numbers are but i need detailed instructions on where they are.

Engine Number is found :

I think:
Late A12,A14,A15 = Next to distributor
http://nissan1.motadata.co.za/images/969.GIF

I know:
A10 and Early A12 = back of block near the connection where clutch cable goes through to the gearbox.

Yep, dattodude is right. All the ID numbers are stamped on the right side (distributor side) of the engine:

up to 73 -- the smaller of the two flat machined areas to rear of distributor, will say A10 or A12

73 and newer -- the smaller of the two flat machined areas just forwards of distributor, will say A13, A14, A15 or A12A

A14s have "A14" cast into the block (not stamped) just above the fuel pump boss, the others engines have no similar casting numbers.

On the left side of (all/some?) the engines, down low and near rear is a casting number for the original designed car model, like H86, this is the generic number. I think your G number might be this as well, G numbers seem to be for commercials, like B20, B120 or Vanette (see table at end of A-type Cylinder Heads).

can someone post some images of the ID numbers, i can see the flat machined areas, but theres nothing on them, maybe theyve been sanded off? are there any really noticable ways of telling between an A12 or A15? this is pissing me off