You cannot lose with either engine. Same peak HP if you use the same camshaft, but many A15 have a milder camshaft and make less HP than an A14. With the 256 camshaft (stock A14) the A15 will make same peak HP, with more HP at lower RPMs.

Rta will sign off on a14 but not a15 unless you have the car engineered which cost heaps! If u want to go a15 I'd build the a14 block into an a15 using the internals ect then no worries with police, thank my 2c

My post wasnt clear. A14 is the way to go. A15 will cost you $600-1000 to be legal.

Sweet thanks for the feedback. Going by this i think I'll choose the a15!

In NSW the a14 is the best choice due no engineering needed.
Get an a15 for cheap and swap the guts over during your next rebuild using the a14 block.

There's no replacement for displacement.
Words to live by. A15 for sure

If you have the choice of 14 or 15, consider which one keeps you legal in your state WITHOUT engineering.
My understanding is that in WA, going from a factory 12 to a 14 does not require engineering because the increase in capacity is less than 20%
but the swap from 12 to 15 is approx 25% increase. In a crash, your insurer might use this against you if its not engineered.

If either are OK with the authorities, go the 15.

Wandering which engine you can get more power out of. I have the option to put an a14 (round port head) or an a15 in my 1200 coupe. Any help would be great! Cheers, Cleighton