Can anyone help on this?

I have a model of a small enclosure box with NPT holes.  I have generated a detailed drawing of this part and saved both with a part number as the file name.  I need to modify the holes with a different threaded hole call-out and save this under a different part number as the file name.  In other words, I need two separate models and sets of drawings.  I did a "save-as copy" for the model and renamed it to the new part number - good so far.  Is there now a way to save the work already done on the first drawing and save with the second file and part number as a separate drawing file with references only associated only with the new part?  Would doing a "save-as copy" for the drawing using the same file name as the new part work and establish the correct references leaving me with two separate models and two separately and respectively referenced drawings?  The changes are minor so if this is possible, it would save a bit of time needed to regenerate a new drawing.

Thanks!