Nickstone302

Hi everyone. I recently purchased a 91 Nissan D21 from a buddy of mine for $250. The truck used to be a show truck but has recently been placed on the back burner. The body is super clean and the frame is spotless. It currently has a KA24E but I bought it with every intention to put in the SBC that I had from a previous build. Has anyone done this swap and if so could they point me in the right direction once I get it installed. The thing that scares me he most is wiring. Any help is much appreciated.