Gearbox Models

I have started down a long and exiting Road.

I have a Lotus 7 Currently with a Ford Xflow Motor.
For those that have no idea what this have a google its worth it.

The current motor gives about 75Bhp not bad as tha car only weighs about 1000Lb.

BUT

Plans are underway.

The new Install will include a 20V 4AGE VVT They are litteraly being shipped here by the container load from Japan. I have also got no problem with getting a bellhousing to suit the planned route from the motor onto a Cresida Gearbox.

I have a extensive list of Toyota gearboxes that I found on a web site including gear ratios, model numbers and cars they where fitted to.

However the gearboxes are stacked in a warehouse where you point at the one you like had over the cash and leave with your cog swapper. ( a bit like a SPCA for engine parts )

The Problem How do I tell what model number a box is most people can tell me what motor it's from originaly, and from what I can tell its not clearly marked on the box anywhere, surely there needs to be a way to tell. Can anyone help ?

I am looking for a W55 or W58 How do I tell ?