Yeah. please let us know how it goes. I need to do something similar on mine. I have an 86 2wd body on a 80 4wd frame and my parking brake is all jacked up. I've tried to add eyelets but it still wouldn't trust it on a hill.
I have a similar setup, 86 383 4x4 with 33's with a 4l60e. I went with 4.11's and it's pretty much perfect. You could probably go a little higher numerically but I wouldn't go lower.
I saw a post somewhere a while ago where a guy cut off the end and welded the newer hook style to the end of it. That way you can use the new style wipers. I bought some to do this but haven't gotten around to it yet.
I did something similar last week. I have a 2wd 86 cab on a 80 4wd frame with a np205. I put a 1980 4wd high hump in it. I haven't done the carpet yet but I'm planning on buying carpet for a 1980 4wd. Another thing I did to make the floor match better was to get the "rear hump" as well. Its a...