Well, of course the 240 is a much more solid and well made car. I am pretty sure the body was more expensive to produce than the cheesy 700 which is pretty much no good at all except for the lovely 780, a coupe. (Some) kidding aside, the 700 has a different shift support mechanism on the M46, some funkiness to the drive shaft mounts and balances, the hydraulic clutch, and the P type overdrive. Late M46 240s are so rare that I do not know if they got the P overdrive and aluminum cased M46. So there are plenty of drive train differences, if I am defining that properly.