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rear end ratios

To: V8 list <mgb-v8@Autox.Team.Net>
Subject: rear end ratios
From: Jim Stuart <jimbb88@erols.com>
Date: Sun, 04 Jan 1998 19:14:49 -0500
Reply-to: Jim Stuart <jimbb88@erols.com>
Sender: owner-mgb-v8@Autox.Team.Net
Just thought I would share this with the list.

In my GT, I have a T-5 behind my mostly stock 215, turning a modified 8"
Ford rear- one of Glenn's with MG ends. I run 195/65/15 tires on 6-1/2"
rims. Performance was OK, but nothing to buy a full page over. Not quite
as quick as my V8 roadster.

I decided that my original plan of using a 3.20 rear was probably
correct, but I could never find a Ford rear with the correct ratio. A
little math showed me that a 3.50 rear would be good, and in lite of the
T-5 5th gear of .63, might even be better than the 3.20. Besides, there
was hope of finding a 3.50 center section. A message to this list
several weeks ago got a reply from Jack Emery of MG Guys, with a 3.50
pumpkin finding its way to my front door.

Yesterday was swap day. Nothing eventful. Dropped the drive shaft,
pulled the wheels, hubs, removed the backing plates, pulled the axles
partially out, drained, & removed the old center section. "Installation
was the reverse of removal" with a new gasket and approx. 1.75 quarts of
85/90 gear oil.

Put about 150 miles on the car since the swap, and I pronounce it a
rousing success. Much quicker through the gears, and not too big a
change in 5th. 2000 rpm in 5th was 70 mph, now is about 60. I have a
mild Crane cam, and I am running "on the cam" more of the time, the
engine is much more responsive. If  you decide to run 15" wheels, give
some thought to a different ratio than the traditional 3.00/3.07.

Yes, I know the RV8 uses 15" wheels and a 3.00 rear, but that is a 3.9L
engine, may run lower profile tires, is presumably lighter than my GT,
has FI , etc. This is meant to be food for thought, not a definitive
statement of the "correct way to do it".
"Your experience may vary...."

Side notes:
1.  Jack Emery was a pleasure to deal with, broad automotive performance
knowledge. Jack, if you read this, I want a real good deal on whatever
you come up with as a pan hard rod for my B.

2. You can remove the backing plates without disconnecting the wheel
cylinders by either removing the cylinder from the plate, or by gently
bending the brake pipes after removing the tie straps. Either method
eliminates bleeding the brakes. Bending  pipes may result in a crack.

3. I made a simple tool to remove the axles using a large slide hammer.
I found a short (2") section of thick wall square tube 3" x 3", drilled
a hole in one side to mach the end of the slide hammer, drilled a hole
in the opposite side to match the end of the axle. Note that B axles,
and my custom axle have threaded ends. Bolt the tube to the slide hammer
& to the axle & slide away! 3 licks was all it took to pull the bearing
& axle.

4. Boy are V8's FUN!! Its 67 degrees here in Gaithersburg, Md today, & I
have been DRIVING!!

Good weather & a good New Year to all.

Jim Stuart


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