Welcome to the forum! Glad you joined. Glad to meet you.
Don't miss the request to create a signature that outlines your truck. That way we can answer questions more accurately, and w/o having to ask each time. And, adding your name makes chatting with you more personal.
Where are you in Alaska? I ask because we have a map (Bullnose Forum/Member's Map in the menu) and I'd be happy to add you if I had a town.
As for adding 4wd to an F350, I think that is an undertaking. Yours should currently have coil springs, and a 4wd F350 has leaf springs. And, as of 1985, a solid front axle. So my guess is that finding a donor 4wd F350 would be a good investment.
Anyway, start a thread about your truck in the main section. Post some pics. We'd love to see it and to help as best we can.
Gary, AKA "Gary fellow":
Profile
Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI