3.9 Swap?

I've been reading of the 3.9 gear being put into a Magnette. What years or type should one be looking for. How tough of a job is it?

Thanks, Donnie

Use the "search" in this forum, this is covered from time to time. I haven't installed mine yet. An early B is a bolt into our pumpkins, you need to be sure the rear axle splines are the same. I believe it is 25 splines but read the earlier posts for correct info.

You can take the spider gears out of the Magnette differential and install them into an early (pre-68) MGB unit. If you've never done anythign like this, plan on it taking all day. An experienced hand can do the swap in less than 2 hours using a hoist.

MGB used 25 spline axles, Magnettes used 10, so swap the spider gears like Jeff said. Here's a good step-by-step with pictures:

http://www.chicagolandmgclub.com/photos/a_diff/