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MGB MGB transmission information needed

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Michael Oritt

Michael Oritt

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Can anyone give me dimensions of an MGB four-synchro box? Overall length and diameter at the front of bellhousing and where shifter goes into the case would be great.
 
Michael:

I would guess you're not interested in doing a 5 speed swap, but Quantum has those as well as rebuilt MGA units (they might do some upgrading to the MGA trans during their rebuild.....might be worth asking).

-Quatum Transmissions-

And there is some useful info here on putting a B trans in an A. Not exactly what you're doing but it does cover some of the mechanicals.

https://www.mgbmga.com/tech/mga4.htm
 
Michael, call Jim Boffo.


...jus'sayin'...
 
SVRA and VRG rules say I need to keep the same number of forward speeds so the five-speed is not permitted.

Who is Jim Boffo and how do I reach him?
 
PM sent.

He's referenced HERE.

My spare box is the three synchro and buried inna shed. You're likely needing the four synchro dimensions.

NFI here.
 
I was grouped with Mike Zappa at this year's PVGP and was running right behind him in one session, pedaling as hard as I could to keep up. As we went into the left-handed turn in the serpentine I heard him downshift into first and it was quite discouraging as he went up through the gears and pulled away on the short chute to the final turn. That's where I got the idea about putting a four-synchro box in the Courier which would be legal as later cars powered with MGB motors had them.

BTW I see in the profile of his B that he has a Sierra 5 speed box. As I said in my earlier post I was under the impression that we were limited to the same number of forward speeds as originally equipped. Did B's ever have 5-speed boxes?
 
Michael Oritt said:
BTW I see in the profile of his B that he has a Sierra 5 speed box. As I said in my earlier post I was under the impression that we were limited to the same number of forward speeds as originally equipped. Did B's ever have 5-speed boxes?
Click to expand...
MGBs never had a 5-speed from the factory, just the overdrive on either the 3 or 4 syncro box.
 
Michael:

There maybe a bit of creative rules analysis going on.

I got second overall in one of the New Hampshire sessions earlier in the year. When I went over to congrat the guy in the silver-gold 1275 Bugeye that beat me, I noticed he had a Datsun 5-speed.

Maybe these guys are promising <span style="font-style: italic">Scout's Honor</span> not to use that extra gear? Ya think? :wink:
 
Nial--

Right.

I still would like to receive information on the MGB gearcase dimensions from someone. Diameter at where the shift tower mates up to the gearbox and the distance from the front would give me the info I need.
 
Michael,
I have the engine and O/D gearbox out of my early '74 MGB and it's out in my garage. If I understand your questions, here are the answers:

The diameter at the center of the four bolts that hold the shift tower to the gearbox is 25 inches.
That is at a point 20 inches back from the front of the gearbox.

If you need anything else measured just let me know
Bob Thompson
 
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