Thanks all for your help.

Adam: Do you think if there are less gears then there may be less drag hence a smidgeon more power?

At this point I should admit my engines will never be on the road again. They are for my son's Ministock. Sorry to all those purist's out there.

I'm new to Datsuns so please forgive my ignorance.
I recently saw an a12 engine with the distributor mounted up the front below number 1 plug. I own 3 engines, all with it back under number 3. Can anyone give me some history on this and is there any performance advantage with this engine over the more common ones I have?