I agree with Matt. The only thing i would add is that in My 72 145, the factory ran half of the wiring harnes through the pedel mount/steering support bracket. So if you plan to replace the whole pedel assembly (recomended for proper pedel placement and feel) you have to snake the wiring harnes through. That means labeling each wire on the fuse pannel and removing it (at least the top ones if I remember right) from the fuse box.
I modified my automatic X member and I think it works fine for now. If I find one I'll get it. Also don't forget a new speedo cable. You can re-route the auto one and make it work but it will soon give up. Also don't forget to bypass the neutral safty switch so you can operate the starter.

john

Yea... pretty much a piece of cake. The pedal box in your car does have a hole for the clutch pedal pivot, though it's not re-enforced, so you would need to do that, or find a new pedal box. Toughest thing you'll need to find is a crossmember for your O/D transmissions. Or modify your auto xmember.

Of course, you'll also need a flywheel, clutch and cable and pedal, and smaller brake pedal (or cut the one you have). The auto driveshaft *probably* will be about 1/2" too long... unless your transmission has a Dtype overdrive... then it will be fine. But the Jtype ODs are a little bit longer...and being that your transmissions are from late Es, they should both have Jtype ODs. Finding the right driveshaft might not be easy (unless you can source it from the same car from which you find a crossmember), but it ain't too expensive to have it shortened slightly.

Also, you'll have different sized flanges on your rear end and the back of your manual transmissions... someone else will know better as to which flange might be interchangeable.

Overall though, converting a 140 is totally straight forward. There are already holes with welded nuts for the new crossmember location, there is already a hole in the firewall to accept the clutch cable...

My main thing is the price of the car to start with... US$2600 seems awful steep for a automatic 140 unless it is in damn near show condition... The last 140s I bought: a '71 wagon 4 speed in immaculate original condition for $600, and the car I'm currently driving was a faded but rust free '70 wagon auto with 117k... offered to me for free, but in order to sleep, I gave him $100. It now has a (nearly dead) 4 speed O/D.

But, that said, the purchase is up to you, and if its worth that much to you, go for it!

-Matt