The Dissy is on the same side but the changed position... , late model a series shifted the alternator to the other side of the block.

casting numbers, (not serial numbers) are located on the left side of the block (manifold side) usually. I say usually because not every one I have seen actually has a casting number, that said the ones that I know of are as follows;
H10 = A12 70-73
H23 = A12 70-73 GX
H63 = A13 74
H72 = A14 75 and up
G34 = A15 80 up
If anyone knows of any others, please post them

A10 also has the dizzy on the opp side from A14 if i remember correctly.

Quote:
that is why i said, blocks with no numbers, i.e numbers been grinded etc.

If the head is off, you can measure the bore diameter. That's a dead giveway.

Is it a big deal to get a ruler out and measure the deck height? I think it is the best way.

To distinguish between A14 and A15, look for the "A14" casting numbers on the side of the block (not stamped, but cast in). A12s don't have such casting numbers. I'm not sure about A15s.

The 1200 engine, used from 1970 untill '73, & maybee even later in South Africa, had the distributor just above the oil pump. From 1974 the block was redesigned & the distributor was moved back, but it was dimentionally identical. The A14/15 family of engines used a taller engine block, so if you have both, then measure them.

The only other one is the A10, which is not as tall as the A12, but is easily identified as it had only three main bearings.

I have been wondering th exact same thing. lets say if you had 2 engines on the ground, one an A12, one an A15, both with no numbers on them what so ever, are there any tell tale differences, besides the 3?4 of an inch in height difference & engine mounts. is the dizzy located at a different location, fuel pump, enything, a tell tale sign that you could use to determine the difference between an A12 and an A15, it seems to be quite tricky yes? any help is much appreciated.

Sure, the A15 (and A14) is about 3/4 inch taller. You can measure the difference. Drive up in your A12, and measure the difference above the water pump to the bottom of the cylinder head.

I have an A15 that has been stamped with A12 numbers. I just want to be 100% sure it is infact an A15.

Maybe james is wondering if somebody were to stamp A12 on an A15 would anybody be able to tell the difference?