Not really, I was actually referring to the cylinder heads.
I do believe I got the models wrong, but the 748E does have a stepped head for the front cylinder. Whereas other 748's do not, and this means they're not interchangeable.
This was so that they could use a common engine for other bikes (stepped head is required to provide clearance for the front wheel)
[Edited on 10-8-2005 by Mr_S]