There are so many things you can do, it's hard to remember off the top of my head. These blocks oil the same way with the same size passages as the 109 blocks so you can ask in the tech area.
This is what I can think of on mine for reliability.
Bored with a torque plate
Drilled one of the center main oil passages.
Chamfered the oil holes on the crank
Set main bearing clearance to factory. Rods were set .0005 looser because they're expected to distort more than normal from my mods.
High volume oil pump with booster plate. (Much debate on this)
Oil pump gears bead blasted. I know this works, raised pressure at idle by 5psi.
Girdle which included main studs.
Head studs.
ARP rod bolts.
Balanced rotating assy.
Valley area casting roughness ground smooth.
Blocked oil filter bypass. (debate on this also)
All machine work is exact. Cleanliness is extremely important.
If you have the money, I would highly suggest getting the pistons and bearings coated.
Big stacked plate oil cooler.
That's all I can remember as I'm about to fall asleep. I'm sure I left some out.