Engine and Transmission Tech

tips, technology, tools and techniques related to vehicle driveline components

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Todd Somers
Des Moines, Iowa
(7 posts)

12/18/2018 05:54AM

Main British Car:
1981 Triumph TR8 3.5L Original V8 Rebuilt Stroker

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Need Help on TR8 / Supra transmission swap
Posted by: BlackFly
Date: April 21, 2020 10:54AM

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

Art Gertz
Winchester, CA.
(3116 posts)

04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: Need Help on TR8 / Supra transmission swap
Posted by: roverman
Date: April 22, 2020 01:41PM

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.

Don Kelly
Charleston, SC
(130 posts)

07/21/2011 05:13PM

Main British Car:
1980 TR7 V8 Z28 FI ECM 4.0

Re: Need Help on TR8 / Supra transmission swap
Posted by: donkelly23
Date: April 23, 2020 02:40PM

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

dave cox

(72 posts)

04/30/2018 03:00PM

Main British Car:

Re: Need Help on TR8 / Supra transmission swap
Posted by: turbodave
Date: April 25, 2020 08:11AM

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!


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.

Jim Nichols
(2098 posts)

02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: Need Help on TR8 / Supra transmission swap
Posted by: mgb260
Date: April 25, 2020 12:09PM

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 $$$$.

Edited 1 time(s). Last edit at 04/25/2020 12:41PM by mgb260.

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