subscribed! i'm interested in hearing what the pros have to say on this!
I'm gonna say that the rear leafs are gonna be too long, but nothing a cutting torch & welder can't fix. i'm not sure you wouldn't be better off adding a leaf and taller shackles for the rear. plus some strokier shocks... not sure if shocks form that old truck are gonna work for you. would take a tape measure & some research on your part.
on the front, i'd be worried about two things (not knowing the spring dimensions) before even considering if the spring rate would kill you in the cab lol!
1. do you need new cups/perches for the new (to you) springs, and
2. are you putting these springs under the front end of a TTB ranger? if they're too tall, you may end up with this lol: