Just a rule of thumb:

I don't know of any gasoline or diesel engine where the most-forward cylinder isn't number one. Notice the passenger's head sits a bit forward of the driver's? Not all "V" engines are like that example however, and some may instead have the left bank slightly forward, which would make the front driver's the number one on those engines.

This is also true of flat (or opposed) engines, too.

The odd-even, or side to side, subsequent numbering convention is up to the individual manufacturers. Sometimes the other bank's most-forward is number two.

Multi-row radials? Look it up in the maintenance manual! It's in there....

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