I have a spare set of barrels and heads complete for my 749s but nothing for the 748.
are they the same?
I am holding on to them for that reason.

dunno about 749 being the same as 748, doubt it though..

I've a spare set of barrels and pistons for a 748E that I don't need now though.

Mine's a 98 bip with 14,000 on it, the service book has two services in it the first on 28/2/03 at 7729 the last on15/6/04 at 13235 so it didn't have a service for the first four years but it's done 50% of it's mileage in the last two years.
What are the chances of it needing new rockers.

Mine was a 97 748 with 16K on the clock. So you may need replacements, although the 916 is less "revvy" than a 748 so less of an issue.

I bloody hope so.

The wifes unimpressed with the rocker story.
Especially with a little sharpo on the way.