MG Sports Cars

engine swaps and other performance upgrades, plus "factory" and Costello V8s

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4.6 MGB V8
Matt T
New York
(29 posts)

Registered:
12/07/2007 04:13PM

Main British Car:


Tunnel Modifications
Posted by: 4.6 MGB V8
Date: December 21, 2007 04:42PM

I have read a lot of different things about the tunnel modifications required to fit different 5 speed transmissions like the T5, LT77, R380, W58, R154 but I have found very few actual photos showing what modifications people had to do to get each box to fit.

While the Roger Williams book indicates that all the transmission options will require significant tunnel modifications I am constantly hearing people say that the T5 and W58 transmissions can be fitted with “almost” no modifications to the tunnel.

I feel like there is a lot of room for subjectivity in the descriptions of how much the tunnel needs to be modified, and I thought I would ask people to post some close up photos of their tunnel modifications in this thread, so that the different transmission options can be compared side by side.

Thanks


Moderator
Curtis Jacobson
Portland Oregon
(4298 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: Tunnel Modifications
Posted by: Moderator
Date: December 21, 2007 05:11PM

Fair enough... but keep in mind some of the other variables: What year model car you starting with? How far back will you locate the engine? How high will you locate the engine?

Here are a couple gallery pages that come to mind as showing tunnel mods:
Jim Stuart's latest: [www.britishv8.org]
Robert Milks' car: [www.britishv8.org]
Ed Greene's GT: [www.britishv8.org]
Pete Mantell's car: [www.britishv8.org]
Paul Schils' GT: [www.britishv8.org]
(I know there are more...)

I like to include in-process photos with How-It-Was-Done articles whenever I can get them. By all means folks - send them in! I can always update gallery pages too.


4.6 MGB V8
Matt T
New York
(29 posts)

Registered:
12/07/2007 04:13PM

Main British Car:


Re: Tunnel Modifications
Posted by: 4.6 MGB V8
Date: December 21, 2007 05:31PM

Good point I just assumed most people were starting with RB cars and using the off the shelf engine mounting brackets from D&D or Glen Towery, but it would still be nice to see some close up shots that may not have been pretty enough to make it into the how it was done articles.
It might be even better if people describe the set up they are using.



Edited 1 time(s). Last edit at 12/21/2007 05:35PM by 4.6 MGB V8.


Simon Austin
Simon Austin
Surrey, British Columbia
(102 posts)

Registered:
10/23/2007 01:44AM

Main British Car:
1977 MGB V8 / 1970 MGB GT V8 project Rover 3.5 / Rover 3.5

Re: Tunnel Modifications
Posted by: Simon Austin
Date: December 22, 2007 01:00AM

Here's a few of the mod I did in my 3.5 with the LT77. Dimensions are out of the book "How to give your MGB V8 power. Stock RB frame mounts with Clive Wheatly's bushings and engine mounts.
Copy of DSC00028.JPG
Copy of DSC00031.JPG
Copy of DSC00034.JPG
Copy of DSC00043.JPG


PaulV8
Paul Avery
England
(18 posts)

Registered:
11/13/2007 03:57PM

Main British Car:
'78 B Roadster V8 , '96 RV8 , '75 MGB GT Jubilee '77 B Roadster , '71 B Roadster , + others

authors avatar
Re: Tunnel Modifications
Posted by: PaulV8
Date: December 22, 2007 02:13PM

Although the cutting of the tunnel and boxing for the LT77 is the "official" way to do it, it's not the easiest.

If you remove engine and box from car and dash centre console you have access to the area you need to modify. On the rubber bumper car you need to rasie the ridge that protrudes down from the main dash supporting pannel and the area of tunnel slightly back from this. It's clearly visible under the car. I found a 14lb sledge hammer and some accurately placed blows allowed plenty of room for the LT77 and no need to cut and weld a structural part of the car....Remove the access plate that covers the top of the gearbox where the gearlever exits to make it easier to bend. I cleaned it all up after and repainted it.

I'm not saying it's the best way, it's just the way I did it.


rficalora
Rob Ficalora
Cypress, TX
(2310 posts)

Registered:
10/24/2007 02:46PM

Main British Car:
'76 MGB w/CB front, Sebring rear, early metal dash Ford 302

authors avatar
Re: Tunnel Modifications
Posted by: rficalora
Date: December 23, 2007 09:37AM

Here's all I had to do to fit a T5/302 combination... The piece on the left afforded about 1 1/2" of extra room. On the right I used the BFH approach to gain about 1/2" of room...

Trans Tunnel Modifications.jpg


40indianss
don foote

(27 posts)

Registered:
08/01/2013 04:35PM

Main British Car:


Re: Tunnel Modifications
Posted by: 40indianss
Date: January 15, 2017 02:59PM

I modified the tunnel as Simon did his and it was not that difficult to fit a ford t5 and d&d bellhousing. To me it seemed preferable to beating it to death with a bfh



burner1
Gary W

(212 posts)

Registered:
09/24/2011 09:59AM

Main British Car:


Re: Tunnel Modifications
Posted by: burner1
Date: January 18, 2017 04:41PM

I put my V6 in a 64 which had a narrow tunnel. All I did was drop in the motor/trans and cut out where it hit. I did this several times till it was clearances then welded on a wider area tying in the holes:

[www.rc-tech.net]


MustangSix
Jack Collins

(28 posts)

Registered:
12/16/2011 10:53AM

Main British Car:


Re: Tunnel Modifications
Posted by: MustangSix
Date: January 19, 2017 03:40PM

Rob, those pieces you put in look like they were necessary for the bellhousing, not necessarily the transmission. Did you have to clearance anything further back?

When we put the Zetec and T5 into our 79 we didn't have to do anything to the tunnel but we were using a 2.3 bellhousing which is a lot smaller. But the transmission clears well.

We had to be careful that the driveshaft didn't foul the ebrake.


rficalora
Rob Ficalora
Cypress, TX
(2310 posts)

Registered:
10/24/2007 02:46PM

Main British Car:
'76 MGB w/CB front, Sebring rear, early metal dash Ford 302

authors avatar
Re: Tunnel Modifications
Posted by: rficalora
Date: January 19, 2017 08:35PM

Good point Jack. Mods I highlighted were for the bell housing. The only tunnel mod I had to do was to cut an access hole and make a cover plate for it. Access hole was needed to install my VSS (and remove it if/when it needs to be replaced). The 94/95 Mustang T5 I used has the VSS at a point too close to the tunnel to install/remove it without that access hole.


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