I may be wrong, but I don't think there's a difference in the dash side of the harness, it should be set up to accomodate tach and non tach models. I put an sr5 cluster in my 81 2wd that came without, and didn't have to change anything for it to work
![I Dunno... :dunno:](https://board.marlincrawler.com/Smileys/marlin/dunno.gif)