MG Sports Cars

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

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7399MGM
Norbert Sliwinski
Pennsylvania
(11 posts)

Registered:
08/04/2018 08:01PM

Main British Car:
1973 MGB GM 3.2l V6

Rear Axle
Posted by: 7399MGM
Date: February 20, 2019 03:39PM

What is the best rear axle/disk brake combo for MGB - 3.4L V6 with T5 tranny?


mgb260
Jim Nichols
Sequim,WA
(2463 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: Rear Axle
Posted by: mgb260
Date: February 20, 2019 08:00PM

If you have the V8 T5 with 2.95 first and .63 OD it will work fine with the stock 3.91 rear. If you have the V6 T5 with 3.75 first and .72 OD get the 3.31 rear gears. Or a narrowed Ford, Chevy or Jeep rear axle. Scarebird has a disc kit for the MGB rear.



Edited 1 time(s). Last edit at 02/20/2019 08:56PM by mgb260.


7399MGM
Norbert Sliwinski
Pennsylvania
(11 posts)

Registered:
08/04/2018 08:01PM

Main British Car:
1973 MGB GM 3.2l V6

Re: Rear Axle
Posted by: 7399MGM
Date: February 21, 2019 07:50PM

Jim,

thank you for your reply. I do have a V6 T5 combination. I am guessing you are referring to the tranny having a 3.75:1 ration for first gear? I do not have a OD however the tranny is a five speed - I do not know the gear ratios for all the gears. I do believe you mean getting a rear axle with a 3.31 ratio? Also, I am installing fender flares and therefore would like to have wider rear tires. So the axle
( I like GM with disk brakes ) would need to have a certain length, right?
I was trying to attach a pic but got the over 600Mb error) I still l don't know who to attach pictures I have no control over the Mb per picture.
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rficalora
Rob Ficalora
Willis, TX
(2764 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: Rear Axle
Posted by: rficalora
Date: February 22, 2019 12:03AM

Norbert, when folks refer to a V6 T5 or a V8 T5, they're referring to the original motor the T5 was designed to go behind. I'm not sure how to best describe it, but there are actually a lot of different variations of T5. Different versions will have different gear ratios, different size (diameter, length, & spline count) input shafts, different length tail sections, etc. There's a good article here to learn more... [www.britishv8.org]

Also, on a 5 speed, 4th gear is typically 1:1 ratio and 5th is something smaller (.63, .72, etc). That is your overdrive gear.


7399MGM
Norbert Sliwinski
Pennsylvania
(11 posts)

Registered:
08/04/2018 08:01PM

Main British Car:
1973 MGB GM 3.2l V6

Re: Rear Axle
Posted by: 7399MGM
Date: February 26, 2019 02:44PM

Jim, thank you for the clarification. I have a 2.8L V6 out of a Chevy S10, the engine has been bored out 030 and has a crankshaft from a 3.4L chevy engine. The T5, I believe came out of a Camarao, as did the EFI. The S10 have a carburetor setup. I have the correct bellhousing with external clutch cylinder. I did use the article you're referring before I purchased the tranny.
Any recommendations regarding which rear axle I should be looking at? Preferably with a disc brake ( alu caliper) set up, and the proper gear ratio. I am in the process of selecting the proper tires size based on the engine, transmission and axle ratio.


MGB SS
Joe Schafer
Central Michigan
(150 posts)

Registered:
10/23/2007 06:46AM

Main British Car:
1971 Mgb 1991 5.0 Ford

authors avatar
Re: Rear Axle
Posted by: MGB SS
Date: March 04, 2019 07:38PM

Norbert
It actually sound backwards but pick the tire size and wheel to fit your car then figure axle width and ratio but as mentioned above the T5 that came out of a 6 cylinder car usually have a different 1st and 5th gear ratio than the ones that came behind a V-8


perrymgbv8
Perry Stephenson

(188 posts)

Registered:
12/06/2007 02:50PM

Main British Car:
Re: Rear Axle
Posted by: perrymgbv8
Date: March 06, 2019 03:34PM

I think that D&D fabrications (aluminium V8) still offer a 10 bolt rear axle with disk brake conversion that bolts straight into an MGB?

[www.aluminumv8.com]


I managed to modify my original MGB V8 rear axle for racing. I know this is NOT for road use. But I am proud of what I managed to fit inside the Factory MGB V8 axle case and still use the 43 year old ring and pinion gears on a Ford 9" spool.

Ford 31 spline spoll with MGB diff gears.jpg



MGBV8
Carl Floyd
Kingsport, TN
(4512 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: Rear Axle
Posted by: MGBV8
Date: March 07, 2019 12:03PM

As you should be, Perry!

That was very slick, & so cool to see it work out. Sadly, that is beyond many of us.


tbo
Tim Body
St Thomas Ontario
(221 posts)

Registered:
01/27/2013 06:47PM

Main British Car:
1954 Triumph TR2 stock 2 litre

Re: Rear Axle
Posted by: tbo
Date: March 07, 2019 11:30PM

Norbert. The T5 you bought hopefully has an aluminum tag on the tail stock bolt on the upper left side with a number starting with 1352 and three numbers after that such as 142 etc. you can look up that number in the article referred to and that will give you all five gear ratios in the trans. then you can think about rear ratios and tire size from there


MGBV8
Carl Floyd
Kingsport, TN
(4512 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: Rear Axle
Posted by: MGBV8
Date: March 08, 2019 09:11AM

I agree with Joe's advice. That is the way the hotrod/streetrodders do it. Get the tires & wheels (or, at least, figure that part out first) and go from there.


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