If you do the Nova sub. You must measure real good, you must also be able to set your proper ride height before you weld it in. You must also do an excellent job of welding, scabing, boxing. Remember you are cutting your truck in half.
You can do this yourself. I can't do this in my shop for insurence reasons. If i did and a sub framed car or truck were in a wreck, ALL the insurance companys want to sue the shop or person who cut the frame in half. What i'm trying to say is if you don't have experence with these crafts . The sub frame is not the easiest swap to do.
Still want to do it ? OK then hunt up as many old Magizine artcles on this subject and do your home work well and your swap will come out good. Good luck with your project.
Regards, HonestFrank