if you know of anyway please let me know also if you know of any websites with the parts please give websites. thank you

Anything is do-able if u have the proper tools & skills, First off u will need a donor vehicle, for the 4wd running gear.most likley u will need a chevrolet trans/transfercase,late models like yours have a left hand front output versus the older ones which r on the right. Therefore u will need to find a mid to late 70 is ford front axle .that is the easy stuff then brackets/spring hangers/brake plumbing,driveshafts,exhaust modification & steering parts will need to be fabricated. this is where a good welder & plasma cutter come into play. there r many many variables inthis swap such as 1/2 ton or 3/4 as both front rears will be different in there mounting abilities. one has coil spring the other has leafs.also u will need to keep in mind u r going to have to make adjustments for gear ratios front to rear they must matchUnless u want to keep ur stock tranny & use a divorced transfercase which case u could run a rear with the pumpkin on eitherside depending on what u get the t-case from. whis will require a jack-shaft from the tranny to t-case. Also l am sure ur van is 6 lug so if u use a ford front rear u will have to redrill the rotors for ur lug pattern. Or possibly swap in a matching back rear from the donor vehicle. l could go on for a long time about what u might run into on this so think it out carefully. There is a company called Quigley that does 4wd van conversions & unless u r a expereinced welder/fabricator l would definatley leave the job to them it will be much cheaper in the long run.