how far do i go

[HandyAndy]

i,ve started cleaning up my donor engine, stripping bits off it etc & a general clean up, its a 1.8cvh which i only plan to use to get me thru iva & then put a zetec 2ltr in, so as per title how far do you think i need to go with this engine?
my thoughts were to replace/ renew the following.....
plugs
oil & filter
clutch ( stripped it today & its had it )
exhaust gasket ( fell apart today )
alternator belt ( its cracking )
sump gasket ( rubber perished )

i have the service book for the engine which is a genuine 90k miles & has had new cambelt every 20k miles so the one thats fitted is only 10k miles old,
so anything else you can think to do to it apart from chop the sump?
took sump off today & not a trace of any sludge etc, i,m well happy with this engine.
i don,t even think i,m gonna take the head off as it was running well when i drove it home 200 miles when i bought it.

cheers
andy