To a large degree, you are correct...but, J-type and D-dipe ODs are not the same length. An auto driveshaft should work with a D overdrive, but not necessarily a J-type.

Also, them long speedo cables aren't as easy to find as you might think. Unless I'm missing something... Granted, easy for a '73 or later speedo, but for the early scew-on speedos, it's getting tough. I still havn't found one for my hot rod 145.... though I can't say I've looked too hard.

And yes, from what I've seen, Duane is indeed the ODGuru... and rightly so. I've never followed his good advice though... I just slap 'em in there and see what happens. So far, I'm three for three. I'd be more cautious of the D-tipe overdrives. Experience and intuition tells me they are more problematic.

Sorry about my spelling of "tipe"... It's a moral and religious thing. "D-type" is reserved for my second favorite Jaguar. My favorite being the C-type, aka XK120C

-Matt