spring mount questions

[coggonobrien]

Hi folks,

I gather parts for my 68 swb 4x4 build and had some questions I'm hoping you can help me with. I am wanting to end up with the equivalent of a 4-5 inch spring lift to run 35 inch tires. I want 3/4 spring rate as I will pull a trailer. here's where the questions start are the spring/shackle mounts differant from a 72 and a 73 up and are they differant between a 73 and up 1/2 ton and 3/4 ton. I would like to use 73 up 3/4 ton gear but may have to use the mounts off a 1/2. as for the differance between older and newere didn't know if they were differant which would result in differant lift springs. Finally will 3/4 ton springs bolt to 1/2 ton mounts?

Thanks!
David