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MG MGB GT V8 Factory Originals Technical - T 50 Transmission

Can anyone here give me their knowledge/opinion on this transmission?

Also a resource for a 215 V8 4 speed bellhousing.


Mike, you'd be better off with a T5. Having broken two T-50's I can say with reasonable authority that they are not suitable for an engine developing over 200hp and the shifting qualities aren't nearly as good.

However, if you have one on hand I might be interested in it as I need a replacement as an interim solution while working up another power train, as I recently grenaded the second one and I don't want the car to be down for two years. By summertime I'll be looking in earnest.

But regardless, the answer is that yes it can be made to work, but no it isn't that good of a choice given the availability of better ones.

Jim Blackwood

What's a T50? Numerous transmissions get referred to as T50, or T5, or similar. I don't know if these are manufacturer's designations - in which case we need the 'name - or just sloppy referrals to the fact that it is a transmission = T, with 5 speeds = 5 or 50. This is a serious effort on my part to figure out what folk are talking about, as I am also studying various retrofits.
FR Millmore

I believe the T50 was the 5 speed transmission originally used on the Cosworth Vegas and some other mid 70s GM small cars such as the Monza, Starfire, and Sunbird. They were only used behind 4 cylinder and V6 engines, too low a torque capacity for even the smallest V8. IIRC 225 foot pounds. Very compact box, quite a bit smaller than the T5. The shifter location was about 3" farther back than the BW T10 4 speed box. I was planning on using this trans behind the 2.5 litre GM 4cylinder in a couple of street rod projects til a job change forced me to sell off the projects.
Bill Young

T5 and T50 are two totally different series of Borg Warner five speeds. The T50 came first. You could find it in 70's cars like the Chevy Monza. It was a smaller and lighter duty tranny - it only weighed 65 pounds. Depending on application, the tranny came with different gear ratios. If you don't need the extra torque capacity and can find a T50 with appropriate ratios than you're in luck. There was an excellent article on T50's in Volume VI, Issue 2 of "The MG V8 Newsletter"... but it hasn't been digitized and made free online yet.

Probably even moreso than the T50, the T5 was used in a pretty broad range of applications and therefore you can find them with different mounting features, different shifters, and different gear ratios. Also, the T5 series trannies were upgraded during their production run. The later T5's are sometimes called "world class". As a general rule, most Buick/Rover powered MGB's will probably want a T5 from a V8-spec 92 or 93 Camaro... but there are lots of related issues (like your driving style, tire size, and rear axle ratio.)

You can read a bit about T5's and see a pretty good picture here:

The How-It-Was-Done articles on the British V8 website will show you that quite a broad range of transmissions have been successfully used in MGB's. Here's an index:
(Note the fifth column...)
Curtis Jacobson

"too low a torque capacity for even the smallest V8"

Actually, with all due respect, the Chevy Monza was available with a T50 tranny used in conjunction with their 262 cubic inch V8.
Curtis Jacobson

Thanks guys for the info.

I'll give some other info on what I'm trying to do.

I have a 215 HI engine.

I have a T 50 transmission.

I'm trying to build a vintage racer GT on a budget.

The T50 is lighter = pro

Parts to repair = con

Low torgue = pro ?

Mate to a stock 3.90 MG diff with a stock 215 HI?

Your thoughts appreciated.

Thanks, guys. I'm not into v8s, but am nonetheless interested, mostly looking for alternatives for 4s. There is a Toyota T50 too, not the same atall. There is a Jag XK project that wants 5 gears though...
FR Millmore

The T-50 has a different shift pattern as well. Reverse is in the same location as 1st, on most modern transmissions.
Takes a little getting used to. Similiar to driving an old 3spd stick shift car.
bill jacobson

Anymore the T-50's are a bit scarce and hard to find parts, lots of people don't even know what they are. There were three versions, the most common being the wide ratio used behind 4's and V6's. 1st is too low for a V8 application with 3.90 gears. The least common had a 1:1 5th gear and seems to be about as scarce as hen's teeth, and that leaves the V8 tranny which was a close ratio box which is usable behind a low powered V8 with a stock axle, but not the best choice. IIRC this tranny had two rings cut in the input shaft. This one has the highest torque rating at 205 ft/lbs and was used behind 260 and 262 V8 engines, had a 3.10 1st gear and a .84 overdrive.

From the torque rating you can see why I wouldn't recommend it for any performance 215. Though it might seem from the application that it is strong enough, it will remain a "weak Link". Aside from that the shift pattern has a standard "H" in the top four gears but has 1st below reverse on the left with a spring detent, making shifts into 1st more difficult than is desireable. If the reverse blocker fails a shift from 1st to rev. is likely. Then by comparison with a T5, the shifter is very heavy if the shift arm is shortened and a long throw if it is not.

Having lived with this tranny in a V8-MGB for about 20 years and having driven T5 equipped cars to me the choice is a simple one. The T5 is stronger, shifts better, isn't much heavier, is more available, and is not likely to break. That's the one I'd have to recommend, and the only reason I'd consider putting a T-50 back in my car is because it is set up for one and I need a cheap interim solution while I prepare an upgrade so that I can drive it this summer.

Jim Blackwood


The T-50 will be okay behind the 215 if you don't warm it over too much. Kurt Schley ran one for years in his Olds 215 MGB.

I have heard that unusual shift pattern referred to as a "road race pattern". First gear is not used once underway, and on a tight track the 3-2 downshift would be a snap.

There was an excellent T-50 article in one of the earlier MG V8 Newsletters. If you are still considering it, I can dig it out & mail you a copy of the article.

No one answered the bellhousing question. Factory Buick 215 bellhousing are getting scarce. There are two that will work. GM made a 3sp/4sp combo & a 4 speed only version.

Aftermarket bellhousing are available from D&D.
Carl Floyd

Thanks Jim and Carl,
Your info is appreciated. Seems that the T50 has its issues and I will re-think the set up.
If I decide to abandon the T50 what do you think this is worth. I have some other issues to consider.
Thanks again.

Mike, I don't know what the value might be, but these guys might be interested or have information.
Bill Young

Mike, I don't know for sure, but I would guess around 100-150 bucks with the close ratio box being worth more than the wide ratio one. A few years back I was able to buy one for $100 and another for $80. While relative scarcity and inflation should have increased the cost, limited demand will have worked the other way.

Jim Blackwood

If you do sell the T50 and Jim does not take it, I need a spare as well. Mine current T50 has a wine to it and not sure how long to the world it will be.
My email is
Jeff Howell
Jeff Howell

Thanks to everyone here for the info on the T50.
I have decided to abandon this for the T5 due to the application I'm trying to achieve.

Jim and Jeff I will be e-mailing you private on the sale particulars soon.

Thanks again to everyone.

Mike, I'm sure that is a decision you will not regret.
As to whether Jeff or I end up with it, I'd suggest that might depend on which version you have. If you put it in 1st gear and then carefully determine the number of turns for one turn of the output shaft, (use of chalk or crayon to mark the starting points is a good idea) the number of turns should come out at just slightly over 3, (3.10) or just slightly under 3-1/2 turns (3.40). If it is 3 then it is a close ratio box and IIRC it should have 2 rings cut in the input shaft. If it is 3-1/2 it is the wide ratio box and IIRC it has no rings.

As Jeff is wishing to replace a noisy box for continued use he will undoubtedly want the close ratio box, whereas I am looking for a temporary replacement and am simply looking for a cheap replacement of either type.

And Jeff, the same advice Mike got does apply to you as well. It's not that hard to go from a T-50 to a T5 and you'd be much happier with it in the long run.

My 340 Buick core was delivered over the weekend and I next need to find a suitable 200-4r automatic, probably a junkyard unit or a rebuildable core since I've been into GM automatics several times before. That project is at least moving along.

Jim Blackwood

is the t5 and t50 a direct swap.
Bruce Mills

The transmission to bellhousing bolt pattern is the same. Not sure about overall tranny length.
Carl Floyd

I have 3 T-50's of unknown condition, unknown origin. If someone wants a "pig in a poke" and is in the Washington, DC area, let me know.

Jim Stuart
J Stuart

This thread was discussed between 11/02/2007 and 21/09/2009

MG MGB GT V8 Factory Originals Technical index

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