AY12 head was good for 140 HP from the go.

On a 1200cc or some other A series? I know JTS heads have made close to 200 HP but that was on big capacity A series.

an A12 block

140 HP to start
150 HP after more work
170 HP later on

My guess is they were more tractable than a max-ported JTS head. But it's just a guess.

sidedraught,
for example ,the gx head is known to outflow any other production car a-series head.this is under assumption that both are either stock or both equally modified and running similar setups.

http://datsun1200.com/modules/mediawiki/index.php?title=AY12_engine

According to this link in this forum, the ay12 were 160ps @ 8800rpm and Racing trim was reportedly 220 gross horespower.under 1300cc class,220hp gross hp(reportedly) is no easy feat! Same cross-flow head on a larger capacity a-series and one can only imagine...

which questions where the power figures came from as its a very rare engine.so only either info from nismo/ factory works or owners of cherrys or 1200s with ay12s can be more credible.better yet a dyno graph with a list of mods attached to it.how many ay12s were produced?

also from link above

Benefits
Using a stock A12 engine block, here are some benefits of the racing-only A12Y cylinder head:

1.It is crossflow, the inlet and exhaust are on opposite sides of the head.
2.Using a hemi cylinder head design, the valves are in better position than in the normal model. Racing trim was reportedly 220 gross horespower
3.The is no heat problem with twin carbs, because they are on diffent side than the exhaust manifold.
4.The chamber is hemi, it can take more compression without unintended pre-detonation (knocking or pinking/pinging)
5.The exhaust side is the same as normal head. The ports are not in same place but one can use standard A12GX exhaust manifold

220hp from 1.3 litre 2-valve engine from the early 70's... I have to say that's a bit hard to believe...
169hp/litre. Do they even get that today from production based engines?

For an AY to make 220hp it would have to be revving very high indeed to match what a big capacity E series would do as with methanol e15 are supposedly making 220-230hp.

The best alfa twin spark crossflow hemi 8v engines are making 220hp to 240hp max and thats with 2 liters!

The Ts cup 1300cc in japan using gx heads and bored to capacities close to 1300cc are rated at 170ps at 8500rpm.Their heads and blocks came in production cars.id say a "nismo" crossflow head specifically made for race use only, on a race 1300 block, 200bhp+ would not seem far fetched.but thats jst my opinion ive based solely on history and achievements of nismo/ factory works "race only" products and cars.

nzdatman, i think its fair to say an engine or car specifically designed and made for the sole purpose of racing is very different to a production engine or production car.they dont put fuel,idling etc into consideration.just pure performance.but as you say 200hp+ is quite a feat.maybe it did, maybe it didn't.no concrete info about these ay12 engine...

Any idea if this is an AY12 Head ?

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darrenwilson i think you have asked a question that only one or two will be able to answer. Only a few know what it really looks like [ay12 head].With regards to the HP i reckon 200 is possible. check out the site Take-off --their small cappucino makes s/where around 200.

You can tell from the photo that is a four-valve head. I don't know which head it is.

The AY12 is a two-valve head. Photos are at AY12.