So this is a very simple question, but it's been years since I did regression and I can't quite figure it out

So basically, I'm given a regression function for predicted weight (w = -99.41 + 3.94 x height) which is in terms of inches and pounds. The R^2 = 0.81 and SER = 10.2

The question is, how can I convert that regression function into kilograms and centimeters? I've tried multiplying by the conversion factors, and for some reason I just can't seem to get it Also, what would happen to the SER? I know the R^2 should stay the same, because it's unit-less and such. Anyone able to help me out here? It would be greatly appreciated if you could point me in the right direction! Thanks!!