They go through the ali water pump, through timing chest cover into the block. So, bit of everything.Is this into an alloy casting ?
Is the pump casing alloy ?
If so, i'd avoid stainless.
Zinc plated/passivated or galvanised (with loads of anti-sieze).
Many different bloody lengths, learnt that the hard way on a d1 200 many years ago.Make sure you put the bolts in the correct holes. I think there are different lengths