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MG MGB GT V8 Factory Originals Technical - Concerning transmission mount

Would anyone have any experience or advise for me? I have long debated a V8 swap in my '78 B and decided to take the plunge. I have located a Rover engine and trans out of a 1980 Rover sedan thru a friend and was wondering how much of an issue keeping the Borg Warner 3 speed automatic attached and dropping the whole thing into the car. I've been told that there is room and since it's cable shifted there wouldn't be an issue with linkage ect. My only concern so far is that it appears that the mounting for the trans is way at the back end. Will I be able to fabricate a mount for it's needed support? The idea of the automatic intrigues me as I've always had 5 speeds. I'm starting to get excited about my upcoming project and hope I can bend some ears here when I get into a pinch. Thanks in advance for all the input. Clint
C.E. Jackson

I used a supra manual box(toyota) so can't help much, but I've seen an auto conversion. The guy made a point of saying that he put the kick down cable on the throttle lever, which is a fairly minor point to make, so he can't have had any trouble with tunnel clearance. There was some mention made of "using the right box". This implies that some varieties of auto box (like his) fit without any tranny mods, others are taller. The '75plus tanny tunnel is so wide that you could fit two gear boxes in side by side, so no problem there. If you need to, moving the the gearbox crossmember is not a problem. With my supra box it ended up about four inches further back. I simply drilled new crossmember holes right through from underneathe, up to the floor and used a 75 by 100 by 5mm piece of steel to spread the load. You can't see it under the carpet. Take care not to do the bolts up too tight if you do this as you could crush the under body channel. Lock nut on the bottom. Some people take the trouble to prize up that bit of floor over the channel and put captive nuts in (or shift the existing ones). If I were doing it again I would make a hole under the seat (where it really can't be seen unless you take out the seat!)) and push a couple of captive nuts in and along to the correct spot, fix it with a centre rivet.Pull it into place with a couple of wires etc. Or use spacer tubes, lots of options. The only thing to be warey of is that the current captive nuts are on a short piece of plate, which can get in the way if you end up relocating too close to the old holes.
Of couse you could approach it from the other end and make up a pair of plates to go on the gearbox and so shift the rubber mounts forward to the MG crossmember.
Peter

Clint,

Check under the thread "3.07-1 gear set". There's a guy there, Mike Maloney, who has a 3-speed auto in his car. He may be able to help you out.
Simon Austin

I put a 700R4 auto in my 70 mgb. The trans mount is stock and mounted on modified mgb crossmember. I just located it and drilled new holes in the frame.
It works great. Mine is an overdrive trans. with lock-up on the torque converter. The overdrive ratio is .70. I left the stock rear end in the car. Eighty mph comes in at just under 3000 rpm.
I really enjoy the auto.

Steve
Steve

Clint,

I have done this conversion more than 20 years ago with a Rover SD1 engine and a LT77 trans.
The MG gearbox crossmenber has to be set further ahead and the LT77 can be directly mouted to the crossmember on the Rover SD1 gearbox mounts (rubber barrels).
For sliding the crosmember fore, the easiest way is to open this area in the floor and relocate the threaded straps.
This setup works since 1984 perfect in my 1973 BGT, having changed the gearbox mounts in 2002, as they had become soft.

Depending upon the position of the engine, there might be some work to modify the gear lever assy to fit in the original position of the B's console, but this is not a difficult job.

Good luck

Ralph
Ralph

This thread was discussed on 06/03/2006

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