273 Numbers Matching car. Should I rebuild or swap engine?

Put that engine aside and pick another sb. 273 cost a lot more to build. Gotta start with commando pistons to start with. They are right around $400-500.
You can use the 273.heads. I believe they are closed chamber small cc heads and will.help compression.
Im doing similar build in my 67 cuda. Just dont have a final direction set yet.