My nephew found me a little treasure at the right price, $00:00. Ex paddock basher and is a real mess but it runs. A14 + 5 speed. Second hand infomation, I haven't seen it yet. I can strip car where it is and take only what I want.
Questions:
1: Did Sunny come stock with 5 speed option?
2: If yes, then which one, overdrive or 1:1?
3: Will I require the whole Sunny dif or just the centre and will it fit into H150 housing?

Here in NZ all our a14 round headlight sunny's had the dogleg 60 series 5spd. (AFAIK)
And I'm pretty sure that All our A15 square headlight sunny's had the H pattern 60 series 5 spds. They were all overdrive 5th gear.

Looking better all the time!

The 5 speed was not a listed option in Australian B310's & all of them got the A12 with the 56A gearbox except the Sportswagon which came mostly with the A14, & some with the A15. Both had the 60 series four speed.

Having said that, I believe that a small number of coupes were landed here at the end of production with the five speed.
Since the only five speed at that time was the 60 series, which were used only behind the long stroke engines, it would be fair to say that these coupes had either A14's or A15's.

Oh yeah, the way I remember it, the person who reported these said that the ones he saw, or were aware of, were sold in Queensland.

As for the diff ratio, it's probably still the same ratio as your stock 1200 coupe at approximately 3.9:1(3.89:1). The difference in strength is negligible. The best bet is to get a H165 1200 ute housing & axles,they'll go straight into your coupe, then you can get a 3.7:1 diff ratio from either a stanza or an early bluebird 4 speed sedan.You do have to shorten the tailshaft, however. A 1200 wagon I had with A14/5 speed/3.7 diff used to cruise at about the legal limit on a barely cracked throttle & 40 MPG at least. All my mates in their Beetles would have to stop twice each way to fill up, & I'd do the round trip on 1 tank.

I have one for sale $850 in Perth if anyone is Keen