340 four speed combo for 340/360 with 727 combo

Well then, I guess you already know, that during the swap you will need to get the right Flex-plate and or Weighted convertor.

Have you considered a diaphragm clutch.
Mine is easy on the knee and was more than I needed so I softened it yet more. Depending on your application, you might be able to keep at least the standard over-center spring. And
If this was an original slanty car, it will have the wrong pedal-box in it, making extra work for the leg.

And of course, if you really like the manual trans (as I do at 71 years old even), there's always the option of hydraulic throw-outs.
Just trynta help.