I haven't seen one swapped with a GCV190 yet. I know the older Timemasters came with a smaller engine, a 190cc Briggs I believe.Not to highjack, but with your OPE experience have you ever seen a Timemaster swapped with a GCV190? I saw someone do it online and rejetted the carb to allow a torque increase to better match demand, but I would be hesitant to do this going to that small of a displacement for this deck.
I'd be curious to see if the GCV190 had enough power. I have two of them, one on a logsplitter and another on a pressure washer and they are plenty powerful enough for that, but not sure about thick grass.