Paul
The A13 was a stocker. It came to us as a partly dismantled & incomplete engine, but there were no special parts in it at all, just cast pistons, standard crank & rods, no special work on the block & a stock head. The rods went into a 1200 motor with A14 crank & 77mm, A15 pistons. That 1200 coupe hauls arse.

The block will be built up for my sons 120Y from leftover parts laying around. I will probably use the internals from my 1200GX engine. With a half mill overbore, it can use my old pistons & i have a late A12 GX cam just gathering dust on my bench. The A14 carb will give it something to suck on, & with an oval port A14 head, it should run sweetly.

If you can temporarily slip in your race engine, that fork lift should peak out to maybee 15kph. With rear steer, even at that speed, you're taking your life in your hands.

Could you use an a14 block with a12 gx crank rods, deck the block and use aftermarket pistons??

A14,15 blocks rule.