Head will be well and truly shagged, the guides especially, but also likely a lot of the exhaust valves will need binning, as may have got very thin around edges.
The guide wear on the yb is a big issue, the best material for new guides is COLSHIBO, which is what I have in mine, I caught mine just in time as some pillock(ford dealer) had bodged the previous HG repair before I got the car, and the exhaust valves ground so thin they must have glowed!!
I've just rebuilt mine, after 200,973 miles on original bottom end, it has even gone back together with the originally fitted thrust shells, and still only 4 thou thrust!!
I used std bearing shells, and std oil pump, but every tolerance was checked first.
My crank is on std grind, and didn't really need a polish.
I have the history from day one so know mileage is correct, I used a group a HG, the dizzy is modded with oilite bearing sleeves.
At your power I'd seriously consider a different inlet cam, exhaust is fine as std, a BD15, and some mild head porting will work wonders before set up/mapping.
tabetha