The sump from a Sunny [B310] A12 will bolt onto the block of an A15, but the rods will hit on one side.
Original A15 sumps have 'power bulges' on one side to clear the rods of this long stroke engine.

If you have a look at your oil pan & compare to the Vanette one, you should see any discrepancy. I believe [but can't guarantee] that the Vanette sump will fit the Sunny chassis.

Called a wreckers today and they suggested that the 1200 sump does fit without any problems! Has anyone done the same conversion and used the vanette sump?

Its quite difficult to ontain a sump from a 1400 or 1500 sunny, this is the reason why Im asking this question!

Original A15 sumps have 'power bulges' on one side to clear the rods of this long stroke engine.

So a12 sump will not fit, however a mate has an a15 out of a vanette in his 1200 and he had no problems with fit apart from engine mounts of course. which as you have a sunny and not a 1200 you will not have engine mount problems.
Cheers

Oh as for Wreckers telling porkies, so your in adelaide i guess you phoned Grand Theft Auto. They will say something like 'bloody oath mate an fj20 will fit' 'nah no modifications mate, here have a vb', just to sell you one...
Just go down u-pullit and have a look at a vanette, im sure you will be able to see whether it'll fit or not.

Go with whatever's less expensive and less use on it. They are both great engines.

The A14 and A15 have same peak horsepower usually (may depend on country or car model), but has a different feel. The A15 has more low-speed horsepower (torque) than the A14, so it feels less 'peaky' and therefore feels 'slower' than the A14 -- even though it will accelerate your car faster.

Ask the man who's had both A14 and A15 in his 1200. Given the same carb, heads, cam, and exhaust, the A15 is more powerful. But with the same peak HP since the limiting factor is the carb, heads, cam and exhaust.

I dunno if A15s can easily be modified to rev over 8500 rpm. I rode in one A15-powered 1200 that did 8000 RPM. Sounded nice!

The vannette motor will bolt straight in. Just use the mounts and brackets off the A12. The sump will fly in, so don't worry about changing it.