Jack,
At the time I had the guy look at the transmission, I was already thinking about doing the Rivergate conversion. I had pulled the engine and transmission from the car and was starting a clean-up/rebuild of the engine. It probably didn't need it, but the car had been setting for quite some time and I found one of the cylinder's compression was low, so I thought I would 'go stupid' and pull the engine, rebuild, it and put things back.
Well, pulled the engine, then thought about it 'crunching' every time I went into reverse, then about how it was strting to get reluctant at going into 1st, then the slight chunk into 2nd, etc, etc...Since I had the transmission out, I took it to 'a guy'(local transmission shop), who took it apart to tell me what he would charge to rebuild, then he started talking big bucks saying it needed more than what you are indicating. By then, I had located the appropriate Datsun/Nissan 5-speed for $150 and talked to the Perry's about a Rivergate kit. It turns out the numbers were almost the same as having my old tranny rebuilt by 'the guy', so I went that route. Due to my work, my laziness, and other family things, it took almost 3 years to complete the work. I am really happy with the new setup... Highway speeds are much better, but I do wonder about originality and how hard it will be to find parts for the RG setup in the future.
Larry