I found very little info when I did my A15, but its a damm strong little motor now and your welcome to the info I have...

I kept crank stock, ballanced
I kept rods stock (small ends enlarged for mazda pistons), ballanced
Mazda E5 pistons custom machined to flat top, ballanced
Block skimmed to give pistons .4mm above deck height
Head full ported to straighten up ports
Aftermarket valve springs
296degree cam with 7mm lift at lobe
as well as good supporting mods such as reworked dissy, well set up 40's, good exhaust system ectr. I have already been into the mid 14's with it which isnt bad for a car used as an every day ride as well as racing in Marque historics.

Search on here and the answer will be found. Use the key words Subaru piston. That will get you started with a build that was about the best way to do it less expensively. Good luck.

hey, i have a 1200 coupe and i want to build a tough a15 for it im just trying to do some research so i know how to get the most out of it, i already have twin webbers and a 3kg flywheel. the things i want to know are;
1. how far can the block be bored out to?
2. what pistons shoud i use and with what rods?
3. what should i get the cam ground to?
4. what are some combinations that work really well?
5. how much power could be made by a a15?
any help will be much appreciated, thanks