check play in valve guides and replace on a need to do basis, bores need honing with a fine grit as a min, look for sratches on the bores and check condition of oil scrapper rings as these tend to snap - which leads to further investigation. check big end and main bearings for wear marks which may signal pump problems. recut valve seats. always replace cam seals as these tend not to seal again. get the crank journals checked and polished or rolled as needed. get oil ways flushed. look at hydraulic lifters for scoring on side as these cause oil leak down pressure losses.
as a min you need:
new big end bearings (£20)
new main cap bearings (£30
new pistons rings (£80)
hone bores (£25)
oil pump clearances checked, new relief valve and spring
crank journals checked, work as necessary (£35 polish)
bottom end gasket set (£25)
valve faces/seats recut (£2 per valve)
new valve stem oil seals
new cam seals
head gasket set (£40)
all new bolts and fixings
Usually best to get the head decoked and block chemical boiled (both for £40)
prices are just guidelines for some of the stuff i've bought previous, i imagine they are still round about todays prices......