Backspacing -70 Chevelle

[Stem]

Hi all.
I'm trying to get a simpel yes or no answer on this questione: I want to use the Coys C5 18x8 with 5,5" bs, will theese fit?
If not, could some one please tell me the right BackSpacing for my Velle?

I've tried to find this out my self, but there are no conversion table from inch to mm that I could find.... Please help a lost Norwegian fool here