I thought 74 144/164 rear spring assemblies where the same as early 244 with the exception of metric fasteners. I convert my early cars to late 244 style springs with early short wheelbase conrol arms. Gives a good boost to the 164's handling less plough understeer from the giant lump up front + more traction at the rear.

I did the exact same thing -- I used the springs and mount from the 245 and everything just mounted up exactly as expected. A nice cheap junkyard upgrade.

This was 1970 164 / mid 80s 245

Other stuff that works well 240 140 include:

door weather stripping
door strike plates (early 240s)
under seat spring / wire grid (replaces webbing)

since you've got a 74 you can probably also use carpets as well.

Hi Dave,
That's a big help and a relief to know I can use them and save a few bucks. It sounds easy enough to swap out. I'm not looking forward to replacing the trailing arm bushings. I will be taking the window motors as well and maybe the heater assembly.
Thanks again,
Matt