Yes you can. the oly diff between the d15 and d16 is the stroke. The pistons them self are 82mm? or that may be b-series. I think there 79 now that I think about it. if you are really that interested about it hit up d-series.org. Anything you want to know can be found there.
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http://www.knology.net/~jediklc/D.htm
Right near the top there is a link titled...
More info on D-Series piston swapping and engine building.