can anyone give info on swapping a14 reciprocating parts into an a12 block an what capacity results? I am led to believe the A14 block is taller.

You can not swap the A14 reciprocating parts into an A12 block, but you can use the A14 crankshaft as part of an overall larger capacity rebuild.

To do this you need
A12 block
A14 crank
A15 pistons
A12A or A13 rods [short stroke version]
You can use the A12 rods by boring the small end out to 19mm to take the larger wrist pins of the new pistons. I chose to get the right rods from the US, as I didn't want to risk anything, but I bored out the 1200 rods in my 1200GX when I used the A14 pistons with the stock crank & they have been in service for about 250,000k without trouble.

The crank needs to be reduced in overall diameter in a lathe by a small amount to prevent the counterweights from striking the pistons at BDC.

One of these engines is being built nearby next week, so I will try to get a photospread on the assembly. This will be the second one of these built here

Thanks the info is appreciated.

I am currently building one of these engines, the only draw back is the stroke to rod length limiting rpm due to piston speed at tdc.
street application should not matter as your not turning that kind of rpm mine should see rpm range of 5000 to 8700. hoping to see 150hp at crank I have seen some 1400s at 172hp at 9200 but with long rod engines

Bob, tell us more about this limitation. You surely don't mean that the pistons move too fast (chevy V8s with a much longer rod rev even higher).

Does the dwell of the piston limit the breathing of the engine? With the short rod does it "run out of breath" at 8700 rpm?Would higher cam lifts help?

So can we take it that Bob is building a 'sneaky' stroker engine since he is still going ahead with this despite the disadvantages when compared to a real A14?
Bob, you make me proud. If you push the bore to 77mm [second oversize of the A15] you will end up with 1434cc, which is a 22.46% increase over the stock 1200's original displacement of 1171cc. All of this with factory parts & no real specialised custom machining. [I dont regard chucking a crank in a workshop lathe as 'custom machining']

As a point of interest, I would have thought that the speed of the piston at TDC was zero, regardless of rod length.
The one engine that is in use here is often spun to about 6,000 & sometimes a little more, & he loves it. As I wrote earlier, another one is being built in the same workshop, but in an A12 block this time [the first is in a 1200 block]. I will try to get pictures.

A lot of the race competitions here in Australia are won that way...who can come up with the looset and most flexible interpretation of the racing regs.

Like the HQ Holden racers who remove reverse from their gearbox to add a 5th gear....don't look any different on the outside.

In fact I think all race championships are won in this way..? or am I taking it too far?

so is this what you plan on doing to win with the coupe in your race series is it?
I like the 5th gear idea

the reason I am building a 1400 in a12 block is the a14 block is around 20lbs heavier and I am tring to keep the weight off the frt of the car. the reason the rpm is limited is the rod to stroke ratio a14 crank with a12a rod has ratio 1.57 which puts more stress on the piston pin and piston skirt due to the rod angle at 90 degree atdc and also the piston speed is increased 70 degrees btdc to 70 atdc again due to rod angle. the opisite is happening at the bottom of the stroke but there is not as much load on the piston. engines with high rod ratios can rev higher due to less loading of the piston pin and skirt the F1 engines use a large bore short stroke and rod ratio's over 2.25 to get high reving engines

A12 block weight saving is a very smart move.
Sometimes some motorsport class regs require the original block type to be maintained. This is the case with rally in Oz. P1 Class limit is 1400cc so the A14 crank into A12 block suits the regs perfectly and the capacity can be take out to 1397cc so you run at the top of the class in cubic centimeters. I guess thats why a few of the really quick rally 1200's running in Oz have this set up.
Bobs1200 - you wont be dissappointed with this modification. It's very effective.