People have been sticking RWD Toyota 5-speeds behind everything from suped up 1600 Ford crossflows to inline6's and V8's. Basically, Toyota gearboxes are renound for strength as well as reliabilty, ratio selection and affordability. I have seen and heard many questions regarding differences between the boxes etc. and how to tell which box you have. Having recently switched to a toyota box myself I decided to find out as much as I could.

The Boxes

1. The Spilt-Case alloy 5 speed. 28kgs, excellent for anything up to 1600cc's. Found behind any 2T or 3T toyota engine. Strong and light but not up to really high power 4 cylinders. Great behind crossflow escorts and anglias, datsuns and MG's etc
Gear ratios: 1st 3.58:1, 2nd 2.02:1, 3rd 1.38:1. 4th 1:1 and 5th 0.86:1

2. The Steel Case Celica box. Very strong but heavy 45kgs. Can handle anything up to around 250hp. Found behind all 2 litre Celicas and old Crowns, Cressidas and Coronas.
First gear ratios vary: 3.28, 3.52 common. 3.62 and 3.00 very rare.
All have the same 0.85:1 5th.

3. Alloy Case Supra box. Very strong and light also, 35kgs. Found in most later model RWD Toyotas. Can handle upto and beyond 300hp. Four different sorts: W55, W57, W58 and W59.. pretty much in that order of rarity.
Ratios: W55: 1st 3.57:1, 2nd 2.06:1, 3rd 1.38:1, 5th 0.85:1
W57: 1st 3.28:1, 2nd 1.89:1, 3rd 1.27:1, 5th 0.85:1 W58 is the same except a taller 5th 0.78:1.
W59: 1st 3.95:1, 2nd 2.14:1, 3rd 1.27:1, 4th 1:1 5th 0.85:1

4. R154, pictured below. Very, very strong box. About 45kgs. Found in late model turbocharged Supras (7M-GTE). Much larger than the W* series boxes. Known to be able of withstanding up to 600hp.
Ratios: 1st 3.25:1, 2nd 1.95:1, 3rd 1.31:1, 4th 1:1 5th 0.75:1
1st 3.30:1, 2nd 1.95:1, 3rd 1.34:1, 4th 1:1, 5th 0.75:1

What have I got?

Toyota boxes don't seem to have many distinguishable markings on them. The real only way to know is to check the ratios, especially with the Steel Case box.
Some people say that if the sandwich plate on the Alloy Case Supra box is cast steel then it is a W58 and if it's alloy then its a W57. But this is not always true. However it is a good thing to look for, easily seen as the cast steel sandwich plate is darker. Word on the street is these are the strongest W boxes as the cast cannot flex as much as alloy can.

The R154 appears similar to the W boxes, but it's quite different. Apart from the obvious extra wide body,. the slave cylinder is in the bellhousing on the R154 unit rather than bolting on the outside like the other boxes. The R154 also has four horizontal ribs along the side of the case whilst the W58 also has three.

The only true way to know which set of ratios you have is to count them. Here is an example of what to do with a W* series box.

1. Count the splines at the output shaft of the box.
2. Put in gear, not 4th cos thats always 1:1, but one of the others. Do all of them in turn.
3. Mark the top of the input shaft and the top of the output shaft with a dot of twink/white-out
4. Slowly turn the input shaft one rotation and get a mate to watch the output shaft.
5. Count the number of splines on the output shaft after one turn.
6. work out the ratio as follows:

ie. 21 Spline out-put shaft,
3rd gear, 1 turn of the input = 15 splines at output shaft

15 divided by 21 = .71

1 divided by .71 = 1.41

So ratio of 3rd gear is 1.41:1 

Changing shifter positions

Luckily there are many different shifter positions available for toyota boxes and most of them can be swapped over. Sometimes this just involves changing over the alloy shifter mount. But if you are going from quite far foward to one further back you will also need to swap over the shifter yoke also. This is easy. You undo the nut holding the yoke, then you need to undo all the bolts around the tailcase. Then gently split the tail case from the sandwich plate. Don't dig in with a screw driver because you don't want to munch the alloy. Use something wide and flat like a chisel to pry it apart. Yes oil will go everywhere. Then the shaft with the yoke can be slid foward and the yoke removed.

Shifter measurements are taken from the front of the gearbox,
(not bellhousing) back to the shifter hole.

Top row, Celica 18" 18" 19" and 20.5"
Bottom row Supra, 18" 18" 19" 20.5" 20.5" and 21"

Right is the furtherst back shifter I know off. JZA80 supra rear-mounted on a cantilever sub assembly. 
It will hang the leaver about 20cm off the gearbox end!

Sloppy shifter?

Green Support Bush = toyota PN# 33505-35020
White Pivot Bush = toyota PN# 33548-31010

The little white bush that goes on the ball at the end of the stick is often worn out and creates a sloppy feel. This can be easily replaced. And while you are at it you might as well replace the green ring bush that sits in the cup under the two locating dowels. This will make a huge difference. 

Aftermarket Bits!

There is heaps of stuff available. Dellow automotive in NSW has pretty much everything from short shifters to alloy bellhousings to suit all vehicles. Great if you are in Australia... bloody expensive if you're not.
Other shifter kits can be found here.. but again... pricey! supra/suprainteriordressuplist.htm