Not much work at all, especially if you use the A12A rods.
Mainly just machining the A14 crank to clear the crankcase & then re-balancing the crank.

See http://datsun1200.com/modules/mediawiki/index.php?title=Bored_And_Stroked#A14_Crankshaft_into_A12_Block

Those rods look familiar ...

Quote:

Yes David, thanks for the rods putting them to good use

Kincrome tool box? I wish i had that setup in my a12. Looks good

Whats the benefit of the A12A rods ?

a12a rods have the 19mm pin hole ans are the same lenght as a12 rod, also slightly stronger than a12 rods

The A12A rods are the same length as A12 rods, but have the larger 19mm wrist pin.

Only the A10, 1200 & A12 engines use the smaller 17.5mm pin & all piston sizes larger than the nominal 73mm use the larger pin size. When building an all out engine on a 1200 or A12 block, the usual thing is to bore it straight to 76mm or larger.
These rods can be used with an original 70mm stroke crank & A14 pistons [which use the larger pins], or alternately, if the longer, 77mm stroke crank from an A14 is used then these rods are used with A15 pistons [which use the larger pin].

The A12A is just an A12 with a 75mm bore size [1237cc] & the short stroke A13 from some Asian B310 Sunny models is also just an A12 but with an even larger 76mm bore [1270cc] & the rods from these are dimentionally the same as the A12A.

The advantage of the A12A rods over the A13 ones is that they are easier to find. Easier, but not necessarily easy, as the A12A seems to have been pretty much restricted to the base model of the US B310 [known as the '210'] & most people seem to have bought their new 210's with the A14 engine.