Will 1986 Chevy pickup frontend fit on a 1976 pickup?

No, a 1986 Chevy pickup front end will not fit a 1976 Chevy pickup without significant modifications, and likely not even then in a practical way. The body styles are substantially different. The fenders, hood, grille, headlights, and core support are all unique to each year and generation. While some parts *might* be adaptable with a lot of custom fabrication, it's not a straightforward bolt-on swap.