Rebuilding a 65 273..I need some help.

2465315 – 1964-1965, 273 LA-series small-block, 1.78/1.50 valves, 57cc

2532080 – 1964-1965, 273 LA-series small-block, 1.78/1.50 valves, 57cc

4323302 – 1985-1986, 318 LA-series small-block, 1.78/1.50 valves, Fast Burn, 56cc -65cc

The 302's have a "slightly different" eyebrow chamber and induction hardened valve seats.