Installing a 4bbl on a 273 advice

Mom's 64 Barracuda, stock 273 two barrel, pushbutton 904, 2.94 gears. Early 1980s, put a small four barrel and dual exhaust on it, everything else stock including CR and cam, ran 16.70s. Thinking probably mid-17s stock. So yeah, just the four barrel and dual exhaust made a pretty big difference.