where are you agr012?

In Aus, 120Ys were both fully imported and locally assembled. The fully imported ones (mainly coupes) had a tiny little jap diff with a lift out centre, that's probably identical to the 1200 diff.

Locally assembled models had a much larger Aussie made Borg Warner rear loader diff and are all 3.9 ratio as far as I know. They have a tin tag on the rear cover with the ratio (3.89). Same width as 1200.

These same diffs were used in alot of other locally assembled jap cars in the 70's. If you are after a different ratio, KE25/30 Corolla's use the same diff, and have 4.1 or 4.3 ratios available in autos, manuals had a 3.89. Centres will not swap into the 120Y housing without alot of messing around, but the complete diff (drum to drum) will bolt in to a 1200. The diff is about 2.5 - 3" wider drum to drum, but will fit on the 1200 leaves without mods. Fit the 120Y flange and use the Y tailshaft. You will probably have to pump the gaurds especially on a sedan(depending on wheel offset and tyre size) or get fwd offset wheels. If you have Stanza (or similar) front brakes, it pretty well restores the front to rear track ratio. They also have much larger drums than the 120Y, but the same size (actually the same part No) wheel cylinders. The 1200 brake line will fit, just stretch the bends out a little to get the extra width. Handbrake would be a little more involved, I don't have the handbrake connected, as it's just a competition car.

I have used these diffs with a fairly strong L18, and have only broken 1 centre and 1 axle in 5 years - and only when using lockers.

will the 120y tailshaft will go in with out modification???

The 120Y diff should be plenty strong enough for a 1200 with an A-series engine. Dimlight has one in his car with a Z20E with quite a bit of power, and plenty of burnouts in it's lifetime.

ARGHHHH!!! Hate that noise....

That happened to me. If you upgrade to a 120Y diff then you need to upgrade the tailshaft as well because it wont fit on otherwise.

Don't know about the strength because mine was replaced back in April and it is making a funny sound again although I don't think the mechanics put it in properly as it is leaking oil...

Diff centre and tailshaft were changed on mine...

cruzn through the main drag of sandybay with my fav music track in back-ground ,listening to my a15 gurgle along, decided give her abit out around an intersection,,,,,bang clunk ..clunk vroom....... ...yep ive killed the standard diff in my sedan.... so shes finally home and her bemused owner is wondering what to put under her while she sits there smiling at me. ..i dont really want to put a 1200 sedan standard diff back in her as i know it was pushing it anyhow. i know the ute diff is strong (if i can find one) , do i need to change much to fit it? (eg. tailshaft brackets etc) . i know theres alot of 120whys for wrecking, are they an improvement? is a wagon diff stronger (i know they have higher gearing) ..... im hoping for something that will be relatively simple to put in, that will do the job. theres also a HUGE swap meet on this weekend so i might even get lucky... ..or even find some good car parts..... Any responce to this will be great