i am planning on running an turbo a15 probably putting out around 150hp. what standard a series gearboxes might be able to cope with this. how strong are the stock 4 spds in the 1200? Are the 5spds any stronger?

I don't know if the 5 speed is any stronger but if you do break one your wallet has to be stronger.
I have driven many turboed A series dattos with 4 speeds ( never a 5 speed) and I have never broken one.
I have however broken 2 4 speeds ( one 2nd gear, the other 3rd gear)
one was in my 1200 the other in my 1000 both were natrually aspirated A12's

At the end of the day I wouldn't say they are a really strong box, they will last but it also comes down to how you drive

I have run an A12 GX 5 speed behind my big bore [76.5mm] 1200GX engine for about 15 years. I have driven it hard, but i do not abuse my cars like some do. These early 1200 / 120Y gearboxes, either 4 or 5 speed are the least strong of the range of A series transmisions.

Gearbox life will depend how you drive it. I have known blokes that i swear could break steel balls with a rubber hammer in a sandpit, while others can make the most fragile components perform well & live long & usefull lives. It's up to you.

I smashed a 4sp gearbox, with a mild A14 with twin SU's.

That day I had tuned the SU's perectly and had timing spot on, went for a drive took off in 1st gunned in then snapped second (and did just that)
I heard this almighty BANG then just the noise of loose bits of metal jingling around, I had almost stripped a cog on the cluster (I think)

So I'd go with a 5speed, but to save money in the long run go with a Celica 5sp conversion as it's cheeper to replace a celica box then to fork out another $1000 or so for another A series 5 sp

Well thats my 2cents

Damo

If you can buy, or make, an adapter for the Cillycar gearbox, then that may well be the way to go. These boxes are cheap & strong. The adaption may cost a few bucks, but i don't think you will break one with an A series.
A local racer uses one behind a VERY healthy A15 & it still lives.

The 1200 4-speed (56-series) was just strong enough. Nissan kept the weight down. NOTE: Nissan did not use these behind A14s. I broke my 4-speed soon after installing a stock A15. They were marginal for racing, so as noted here previously the racers were very careful with them.

The original 56-series 5-speed is probably no stronger. But the newer 60-series trans (4 or 5 speed) is considerably stronger. Nissan used them behind A15s. And the 63-series look to be one tough tranny.

Somebody said they thought the numbers were the distance between the two gearshfts.

just depends on how you drive, i have just fixed 2nd gear from booting in 1st then snapped into 2nd (sheared the hole top half of 2nd gear cluster) and thats with a slightly modded A14.

the 4-speeds behind a-14 sunnys are sposed to be stronger but im not sure in which way, i think the gearbox will take it, im bout to put together a turbo a-15 and havent thought twice bout the box, im a fan of dumping the clutch but not big burnouts, depends how harsh you are but i reckon that if ya break a box its more bad luck than anything

If you break the box, it's more bad management then bad luck.

Bad luck is when a major component has a manufacturing defect in it & it fails.

Bad management is when you dump a shock load onto a component that is beyond it's rated capacity.
My early GX 5 speed is getting loose as a result of over 150,000 miles since i bought it, & i ran it behind a big bore 1200GX. It still works fine but could use a major freshening up. If i don't go the CA16/18DE route, then i will rebuild it & use it behind the same engine, but it will be at 1434cc.

Respect your Datsun, drive it hard, but don't abuse it. That's what respect is.

well id have to say mine was bad luck, it was fine, i took it out put it on another notor, and it was screwed when i ran the car

dunno what happened to it, dont really care now either