Just installed a Spicer 5-134X U-joint. The 1310 and 1350 were both discussed at the parts counter. The first one they brough out is for a GM driveline to 9" Ford rear end. The caps were too big for my TH350 yoke and another guy came over and said this was the one for GM old drive shaft to TH350 tranny. It fit and in spite of current drizzle conditions, I'm headed out to drive to install. Going to exhaust man tomorrow afternoon!
Thanks to all and all your suggestions. I knew there had to be an answer and as usual I learn new perspectives on a problem.