I have one reason only to suggest that it is good to put the alternator on the LH side of the block, Phil. More so, perhaps for the 140 than the 120, but nonetheless...

Moving the alternator allows for a rewire that is MUCH better than original. I did not (yet) move the alternator on my 140, but here's why I should:

The physical wiring path on a 140 (and perhaps a 122) is downright STUPID. The alternator output crosses the radiator support to a junction block. From there, it goes to the battery. The battery main lead goes to the starter.

I rewired my 142 to emulate a 240. The main output of the alternator (I used 6 ga) crosses under the crank (a la 240) and goes to the starter. The main starter terminal acts as a junction block (a la 240). This way, the alternator feeds the battery more directly for charging purposes, instead of the original circuitous route.

BUT... this still leaves the main alternator feed running under the crank - and we all know how bad that can be! I was anally overprotective of my lead, to hopefully prevent any problems.

BUT... if I were to relocate my alternator to the LH side of the block, the wiring legnths would be shorter, more direct, and away from any hazards. This is mainly because the 140 locates the battery on the LH side of the block.

The 122, perhaps not as much. I'm not certain how the physical wiring of alternator-battery-starter wiring runs on a 122, but regardless, moving the alternator keeps all the high-amperage wiring away from the hot exhaust manifold.

So while it may not be AS MUCH of an improvement on a 122 as a 140, I still contend that there are enough advantages to at least consider relocating the alternator.

Evan