273 Performance build possibilities.

Wow thanks for the replies! Very cool to see the compression ratios and peoples experience. Certainly a lot to read and think about here.

...@66fs Thanks! The car has a mild 318 and a 4spd a833. Keeping it like this for a while and driving the car, but am considering ideas for a drivetrain overhaul including TKX 5-speed and new rear. But i'm debating on the purpose of the car. There is an idea of keeping the car a driver, but wanting some power, or ability to get more power. Drivable enough I could start it right up and go get groceries, but enough power to have a bit of fun...
Purpose of the car is the first thing to decide. I always liked the 273 as you can drive like a normal engine and if you want to go faster, just let it wind out. You already have a 4 speed. To be honest if you don't have a 273, any Mopar small block will work. You don't have to run a large cam to get a 273 to rev high. What rear and and gear ratio is in the car now?