1986 chevy body on a 1979 chevy frame

I'm currently in the process of building this truck into a 2.5 ton mega truck but need some advice on whether to add to the chassis or rebuild it from scratch any suggestions would be nice or Ive even thought of getting in touch with Bam Bam Bigguns and seeing what needs to be done because hes helped out a lot of the guys i race with such as Twitty and Michell Boniford (god i hope i didnt butcher his name lol) but as of right now its got a stock 350 motor and a 350 tranny with a 203 transfer case, 10 bolt front and rearend, 6in lift on 35's (almost bald btw)