I actually think they're separate designs from the ford Mod motor. The failed attempt at the Retro T-Bird actually uses the Jag AJV8 in one form or another. Jags used to be a PITA to maintain, but after Ford bought them they tended to do a little better with reliability. I actually looked at these motors too, they perform well, they're relatively light, especially compared to the giant DOHC mod motors, and it should fit. Unfortunately, I think there's less than zero aftermarket for these cars.
I just wiki'd the motor and it appears it's been thrown around a bunch of jags and a few fords, unfortunately all autos.
http://en.wikipedia.org/wiki/Jaguar_AJ-V8_engine#AJ35
There also seemed to be a similar problem with them as the BMW's with the Nikasil cylinders, but instead of switching to Alusil, they just sleeved them, so you'd want the iron sleeved replacements.