The worst part for me was having to take off the oil pan to get at the two bottom bolts which thread outward from the block. People have modified that by tapping the hole and running the bolts from the outside like all the others.
On my 235 the cover is held on with slotted screws. I replaced them with same size bolts. Easier to get to and easier to tighten once the fan as such is back on.
I think slotted screws were invented to create cuss words. Hate them!
