How many xmember mounts it got? And there's nothing on either side of the case? Have a look in the wiki at pictures and see what it looks like as without pics it's hard to tell!

most likely a 56A then..

It's a ribbed casing ? No pics sorry .

ribbed or smooth case?

Any pics?

Hi. I just pulled the A series 4 speed out of my spare sedan. It does not have a56 or a60 cast on the right hand side ? It does have some numbers stamped on the top of the bell housing but no letters like most boxes. It looks to have been rebuilt recently as it has new bolts and fresh gaskets and sealant. I have heard this might be a from a 1000 and might be weaker. It was behind a slightly worked A12 and didn't have any problems. Would be good to know for sure what it's from as I'm putting a new clutch in my daily driver and want to use the strongest of the two boxes that I have. The box in the car currently is a 56a and is also working fine . Cheers