KB block and wet sleeve water sealing

I have a KB alloy block which has wet sleeves. The sleeves seal at the base and top with a o-ring.
I cant see the top leaking as its seals against the block deck and head gasket.
What are peoples experiences with leakage around the lower o-ring ????

I will be getting the block dressed up in the o-ring area so the surface is smooth and to correct diameter (nice tight, semi press fit). Of course will use new 0-rings and the sleeves nearly new and fine in the o-ring groove area.
I was going to pick up a low pressure radiator cap as well.

Engine is for a street/strip application. I really dont want to finish my build and then have water leaking into the oil pan......

Any advice from people who have done this before.......