Yep I've done this conversion. Works great too. Used a Toyota box -
they use the same model, a W50 I think, in a range of models, Supra,
Corona, etc. It comes with an alloy or a cast iron case - you want
the cast iron one. There are also two models of gearshift remote, you
want the short one that goes straight into the box not the one that
extends backwards.
The remote is the only real problem with this conversion. The lever
will come out a few inches back from standard if you dont modify it.
This is OK if you are converting an auto or don't mind recovering your
console, but I wanted mine to look standard. You can do this by
cutting off the top of the rear extension on the gearbox, sliding the
"control lever" further along the selector rod, then re welding the
gearlever socket in a new position. There are a number of places here
that do this modification as this box is a very popular one for all
types of conversions. I have seen it in Landrovers and Land Crusiers
with transfer cases attached! Also XJ12's MGB V8's and Cobra replicas.
I used a spare Jag bellhousing I had lying around and just welded a
couple of "bosses" in the back to take the Toyota bolts. I did not
use the top two bolt holes. I understand there is now a ready made
Jag to Toyota bellhousing available in Australia. I had a spigot bush
made and fabricated up a rear mounting that attaches to the original
mounting points of the Toyota box and still sits on the original
spring mounting of the Jag box. I had to lengthen the driveshaft a
few inches and used a Daihatsu Truck 10 inch driven clutch plate
with the standard Jag pressure plate.
The only weakness in the Toyota box is the front bearings. It pays to
replace the front main bearing as well as replacing the front
layshaft bearing with a heavy duty roller bearing in place of the
standard ball bearing. The conversion places here usually do this to
all their boxes before they will sell you one.
The only other thing from memory, was to get a Toyota speedo cable
end grafted on the Jag cable and then get the speedo recalibrated.
I've had this in my car for about seven years during which it has
endured some racing with no problems. I was the first to do it here
and since quite a few jags have had the same conversion. I would have
prefered an all syncro o/d jag box but there are none to be had for a
reasonable price so this was my only option other than a Moss box. I
still have everything so I can convert back if I wanted to.
Ratios are: a very slightly higher first than an all syncro Jag box,
very similar second and third, direct fourth and a .8 fifth compared
with .75 for overdrive. I have a 3.54 diff instead of 3.77 and feel
the ratio are perfect for the 3.4 engine.
Some people thought I was mad when I said I was going to do this to
my Jag, but it is my daily driver and needs to be practical. No one
who has ever driven it has had anything other than praise for it, and
many cynics have been converted.
John McDonagh
Lincoln University
Christchurch
New Zealand
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