273 correct heads?

On my 73 318 block I have cast iron heads 2843675. These were used on 67 318s and 68-69 273s with 2-bbl carbs. 1.78 intake/1.50 exhaust. Small chambers 62-64cc, small ports. I had Basko Engines in Gilbert AZ open valves to 1.94/1.60, polish bowls, used lightweight valves, 320 springs. They did not port match because of some ports having a bolt hole boss near the opening that would force air to center and reduce flow in those ports. Said the gain wouldn’t be worth what he would charge. The guy has a dozen Wallie trophies in his office for winning races as a driver and a builder so I trust him. I added PRW adjustable 1.5 roller rockers and used .027 Cometic steel gaskets. .030 over, dish pistons, Edelbrock Performer and 600CFM carb, Comp Cams 270H with 224 duration @ .050 lift, .470 lift. 8.75 calculated compression, dyno showed 300 hp 350 tq. Not bad for an old Frankenengine.