Need Help on TR8 / Supra transmission swap

[BlackFly]

Hello I have a 1981 TR8 and want to upgrade to the Supra W58 or w57 Transmission and looking for anyone who as done one of these to give me some do's and dont's. I would like some guidance on which use transmission to buy and who has the best kit that will adapt to the 81' TR8... I believe Moss sells one but i think that is for a tr7? and there is a guy in New Zealand that makes a conversion kit also.. Has Anyone done this? Were they happy? Would anyone have any of these parts for sale?  My TR8 has about 300 hp and and I dream of the day to have a smooth tranny that will handle it.  Thanks for your input please contact me tsomers@protonmail.com or call 515-718-5681 Im in Iowa

[roverman]

Friendly question, WHY would you do this ? Consider the painless, lower-cost alternative, the T5 in all its configurations. Bolts direct to TR8/Buick V8. Never look back.   Art.

[donkelly23]

My thoughts exactly,... unless he has a dozen or 2 sitting in his garage

[turbodave]

The easiest thing about the W58 is looking at the one you already have. If you don't have one, then that's your first somewhat difficult part.

The next (and most difficult part) is making an adapter or modifying a bell. Unlike the T5, which has a super-convenient round pilot bore, the W58/9 have a bolt pattern. The guy below went about this in a manner that'll work, but is very labour intensive!

https://www.toymods.org.au/forums/threads/52175-Not-so-DIY-Made-a-T-50-Bellhousing-to-W58-transmission-adapter

The real beauty of the round pilot (T5) is that you can easily use a dial indicator verify location. I found the best way (after I modified a discovery auto bell for a T5) was to weld in an adapter into the center of the discovery bell with the center hole around 1/8" smaller than the final dia, then mounted the bell to the engine, and clamped a ring to the face, and clocked this one in perfectly. Then unbolt the bell from the motor, set on the mill and clock the spindle into the ring, then removed the ring, and machined the center bore to the right size for the T5. Worked perfectly.

I was surprised how far off the original bore was - maybe it had shifted slightly as a result of my welding up the rear face pockets and welding in some bolt mounting bosses into the Discovery auto bell, regardless, it was off by almost 80 thou !

For the W58, you need to do the way the link above did, or find the dimensions of the front cover, and drill your bell to suit.

[mgb260]

There may be a couple of easier ways. D&D has an adapter that mates the 215/Rover to the 60 degree GM 700R4. With that adapter and a Jeep AX5 ( Toyota W58 pattern ) 60 degree bellhousing, may be a bolt up. Don't know the price of the D&D piece. Novak has an adapter to go from the Chevy T5 pattern found on 215  ( Muncie ) bellhousing and D&D bellhousing, probably around $250. Dellow in Australia has one but $$$$.