Does anyone have any dimensions on the original GT V8 transmission--preferably with the bellhousing?  Alternately, any transmission used behind a Rover or Buick V8. I'm trying to do some planning with my Tremec 3550, which I know is bigger--but not sure by how much.  End to end length, shifter to front of bellhousing, width and height would all be helpful.  Thanks much!

Here are some dimensions of the last Rover 5-speed gearbox, R380: http://www.v8engines.com/transmission.htm

I have a Rover 5-speed LT77 box that I can measure for you.

Thanks Jukka.  I also saw that drawing, but I only just now figured out how to read it.  Do you have any insight as to whether the shifter location "works" in a B where it is on the R380 or LT77 (I think they are the same?)?  Trying to also get some idea of relative location of what people typically deal with vs the shifter on my Tremec.

"MGB GT V8 utilised a modified 4 synchro overdrive box that is identical to the 4 synchro 1800 B unit except for the ratios and the bell housing, which mates direct to the Rover block."

I could not find any width measurements for the T-5, but it is a good bit wider than the LT 77 or R380.
 It is likely quite close to your Tremec 3550.  The Borg Warner T-5 length will vary depending on original application.

Here's a pic to show the T-5 next to a LT77.  The shifter location is for a TVR Griffith.

Thanks Carl, that's very helpful.  Do you know if this shifter location is similar to what most people use on their B?

I found this link that compared the T-5 to the Tremec, but no mention of width (although I think the Tremec is even a bit wider): http://www.britishv8.org/Articles/Ford-Transmission-Options.htm  Near as I can tell, the my Tremec has the shifter about an inch farther back than the T-5, due to an adapter on mine to fit the BOP bell housing.   From what I can tell from Jukka's drawing, the shifter location on the R380 is about 20.6" from the back of the bellhousing, so similar to the Tremec.  

Now to see if anyone has insight as to the typical shifter location from the back of a Rover or Buick V8.  And if anyone has information or a link that points to tunnel dimensions.  So far, I have only been able to determine that there's a wide or narrow version--and I was able to find dimensions for a Midget :/

As with the length, it will vary depending on the application.  This link includes the bellhousing.

https://core-shifters.com/pages/shifter-distances

I measured my LT77 box and the shifter distance from the front of bellhousing to shifter is pretty close to 30 inches. There were different versions of LT77 shifters (called "remote" in UK) both in 2WD and 4WD boxes. AFAIK this is the longest version.

Photo of my LT77 attached. Another dimension worth mentioning: mainshaft to top of box is 5,2" . This may give some idea of how much to clearance the trans tunnel.

Carl, thanks again. Another great resource.

Jukka, thanks for taking the time, I appreciate it.

"Another dimension worth mentioning: mainshaft to top of box is 5,2"

A dimension that Google is no help with on my GM V8 T-5.  I do know it is less cause the T-5 fits with a lot less hassle than the LT77.

Carl, that's interesting.  I see that my Tremec seems to be a bit less than the LT77 at a little under 5".  Although I'm under no illusion that this will be an easy transmission to fit

The T5 is the most commonly used transmission because it fits without bashing the tunnel and the shifter comes out in the right place, provided you get the garden variety T5 from a Camaro. The LT77 can be made to fit but the top of the tunnel needs to be modified, either by cutting and welding or some heavy hammer work as I understand it. Haven't done that myself. Also I think the T5 is a little stronger and doesn't have an oil pump that can fail. From what I've heard the 77 could be a smidge easier shifting. As for the ratios it depends on what you get. I have one of the Tremec T5 variants with larger shafts and the ratios in that are as good as it gets.

Jim

The T5 may be a little shorter than the LT77, but it's definitely wider towards to the top because of the top-load (ish) configuration.

The only camaro T5 to use is the early V8 WC one as all later camaro's used a much weaker version of the T5 with lousy ratios.

I used a 99-04 "electronic speedo" mustang T5 in my SD1; these were rated to 300lb ft - almost as much as the 310 of the T5Z, but the 1st gear ratio is a little steeper at 3.31 vs 2.95, but after that, the ratios are basically the same. The T5Z also has a taper pocket bearing, instead of the thrust/radial of all other T5 units, but the stock layout seems to be pretty strong if set up properly.

In my SD1, the shifter was approx 2.75" forward of the stock TR7/SD1 LT77 location, so I have an aggressive dogleg at the base of my shift lever. It all works good though.

If you start with a healthy T5, then  you'll probably find it overall easier than a 3550 - but if you already have one, then  why not try i guess.

As far as shift feel, there is no comparison between a T5 and a LT77. The dual/triple carbon synchros on the later T5s are night and day superior to the LT77.  I recall the 3550 has pretty similar synchros to the T5?

This pic shows where  a number of us did just a little bit of hammer massaging to fit the T-5.  Big notch not needed.

May not always have to do that, it depends a lot on engine mounts, setback and crossmember configuration.

Jim

TurboDave, I mistyped.  I actually have a 3650.  Similar to the 3550, but without the integral bellhousing.  Mine has been built for improved shifting and a high torque rating--it should easily be the best shifting transmission of the bunch.  However...it weighs a bit more than the LT77 but almost 30 lbs. more than the T-5.  The real issue with the 3650 is likely the width.  I haven't tried fitting it, so no idea how tight it will be.

Carl, that pic of the tunnel is very interesting--makes me think I *might* have enough width.  I've attached a pic of my transmission,

If it is narrower than a T56 ( it looks to be), it will fit.  Unless you are putting it in a narrow tunnel B.

Carl,  good to know, thanks again.  It IS narrower than a T56 (see below).  And mine is a 72 GT, so I think that's the wider tunnel (?)

Here's an interesting video that shows the T5 vs a TKX (similar to the 3650) and the beast T56.  https://www.youtube.com/watch?v=P-LDHm68a3o

The MKII was the beginning of the wider tunnel (10-67 for model year 1968)

Glenn Towery managed to stuff a T56 in an MGB.  Glenn's words:

Quote from: mgv8glenBEEN THERE & DONE THIS!!!!!! I was able to get it in without cutting the trans. hump BUT, did I ever work the hump over with a real big hammer! & a grinder on the trans. ribs. When it was all over & done, I will not ever do it the 2nd. time. I was shifting gears ALL THE TIME!

Good to know, makes it sound like a 3650 would be easy by comparison.  And definitely no need for a six speed, with all that torque, in my opinion.

I thought all 3650 did have the integral bell - but that looks like one that uses a special front plate to (presumably) make it able to take the fox or GM bell (depending on the input length). I've never seen that before... Sweet.

Turbodave, yep, they remove the integral bellhousing and replace it with the adapter you see on mine.  When I have a minute, I'll mate up the BOP bellhousing and take another pic.  It was done at Hanlon Motorsport--they sell the adapter plate.  They also replaced the entire gearset and upgraded the spline, to make it stronger and easier to shift.  and then they threw in a short throw billet style shifter.  Should be pretty awesome when I get around to having it behind the stroker Buick 300 I am planning.

In the UK a common T5 variant for Rover V8's was the TVR T5 with the tail housing from a Sierra Cosworth , that is until the prices went through the roof. Both the TVR and Sierra T5's had a 1" 23 spline input shaft. which is NLA, while it lasted it put the gear lever in the correct position.