Ok, a friend and I talked about this to decide.

Keeping budget in mind, what would you do?
Let's say in my case, the car already has a A12 and is already registered with it. The A14 you would have to go and buy and re-register in the car.

I would say money wise it is better to keep A12, but performance wise go A14.

Is there really a huge difference between A12 and A14?
Boofhead once answered me that he owned both and said the only difference is torque.
Why I also say A12 is not too bad is that his little A12 could keep up with some big guns on the track when attending track days making me think that one must not under estimate the A12 engine.

i've had all sorts of combos in the 1200s as well

i would say why spend the money on the a12, if it doesnt change the class your in or anything like that your just kicking youself in the nuts staying a12

i've had worked a12's and a14, a15. personally i think you have to thrash a worked a12 to go as quick as a mild a14, last x-mas we upgraded the rally car to heavily worked a-14 (rule change allowed it now) and we havent looked back

apart from initial purchase price the a14 should not be any more expensive to rebuild

to add to that i just upgraded dattogals a12 to a15 (automatic)

she used to drive everywhere with the foot flat to the floor, now it goes much quicker with only 50% throttle. it just pulls beautifully, like a V8 really compared, in race and street circumstances you can get the job done without thrashing the motor

What about the gearbox. My car is still using the 56A 4 speed.
I doubt it will handle the torque of A14 or even the A15.

1200GXman, The 5-speed F5C56A with the wider gears will break under the torque of racing A14s and A15s, so yes, transmission reliability is a major problem.

If you can find a tranny to take the torque, I recommend the A14 over the A12. You'll be happy with the torque.

If money forces you to keep the 56A box, use a spring loaded clutch disc, rubber motor mounts and a gear oil called Redline Shockproof (made in USA). The shock loading is what breaks the gear teeth. -Peter

1200GXMan, just use a transmission from a 1400 bakkie. It will handle the A15.

Some good answers here,but your question should be which gearbox more so than engine for competition.The distance between 2nd and 3rd gear in all the 4 speed boxes is the killer.Our little A series motors need to be kept in the sweet spot,above 4000rpm or so,so what you want is a dog leg box with nice close ratios and a short final drive ratio.
The A14 and more so the A15 overcome this shortcoming by producing more torque to help drag the thing through this low rpm range but in doing so place a lot more load on the gearbox eventually breaking it.

I,m still getting away with a mild(for competition)A14 coupled to a 56a box all sprung and rubbered but i know it,s only a matter of time.I have a 60 series waiting to go in.If i had a lazy $1500 or so i,d be looking for a dog leg box.

Good point. Yes the 56A 4-speed which GX1200man already has is also a wide-ratio.
Bert are you referring to the 63-series dogleg box? Where do you get close-ratio gearsets?

Any 5 speed with a 1:1 5th gear will do the job as the intermediate ratios are closer.A good friend has a 1200 coupe 1400 equipped circuit car only hooked to a 56 dogleg and never had a gearbox breakage.On any of our tight circuits here he will exit a given corner in 2nd then 3rd &4th briefly before braking,myself along with all my poor friends exit the same corner in 2nd then 3rd and drag it out not even hitting redline before braking and we have bigger brakes!We all have around the same engine performance handling and skill level,but not having to wait what feels like half an hour for the thing to hit it,s straps in 3rd is worth about half a second per lap...add that over 10 or so tours.

Quote:I'll agree with this 100%, however the only A series trans with this ratio in 5th is the 56A, both in GX form & in Option 1 form.
All others [60, 60A & 63 series] are overdrive in 5th.

The 56A is a wonderfull trans & was used widely in competition back when A12 engines ruled the roost [even in 76mm bore versions] but they are light & as has been said several times, do not have the capacity to handle the torque from race engines with anything much longer than the 70mm stroke cranks of the short deck engines.
They simply love the revs, but not so much the grunt.

As for which would prove to be the better race engine, A12 or A14, then Rand for Rand, or mod for mod, [trans notwithstanding] you would have to realise a greater performance potential from the A14.

To quote one of our race oriented members, "Horsepower sells cars, torque wins races."