• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

MGA MGB Overdrive in a MGA ??????

Share this page

B

bluemg

Senior Member
Offline
I recently came by a early MGB overdrive transmission, which I had been searching for, to put in my 1965 MGB.
However as it has sat in the garage next to the MGA, which I drive most of the time, and which has a real strong 1600
motor, the question comes up,
Will a early MGB overdrive transmission bolt up to a 1600
MGA motor?????
 
Blue - I think that you will find that the rear mount on the transmission is different. I don't know about the fit to the engine, but my guess is that it will. If it doesn't, its a matter of a couple of hours of work to swap the OD unit from the MGB transmission to the MGA transmission. The main shaft from the MGB transmission has to be swapped into the MGA transmission, then the OD unit bolts right on. the rear transmission mount will have to be modified to fit the mounting on the OD unit and you will have to make the tunnel fit the remote shifter.
Cheers,
 
If it's a 3-main engine then it will bolt right up. Just make sure the starter is in the same position. If it's a 5-main engine, the input shaft is a different size. You will need to fabricate a new rear transmission mount and possibly hammer out the tunnel a little bit for clearance.
 
Good advice all.

The rear engine plates do vary a bit, so check the fit out. It is easier to swap an early MGB rear plate onto the engine that take all the guts out of two transmissions.

Be aware that the shifter will be right under the heater controls and unless you heat and bend the shifter into an 'S' shape, you will be ripping your knuckles up all the time.

You need to make up a new rear trans mount for the frame - this can involve cutting and welding or can be done without removing the ears on the frame, but this raises the rear of the trans slightly and soild mounts it to the frame with attendant risk of more vibration conducted to the frame.

It is tight near the hand brake and the tunnel will need to be relieved a bit there.

You will also need a longer driveshaft, as the OD trans is shorter. Either that or make up a spacer that fits between the diff and rear yoke with longer bolts. The thickness of the spacer is 1 1/8" and needs to be machined in alloy so that it fits into the diff yoke and driveshaft yoke.

I have found that wiring the switch into the foglight switch on the dash (F=faster!) leaves a stock looking dash.
 
Back
Top