Yeah, I was determined to keep the original motor in the car, but that isn't necessarily the smartest way to play it. I was doing most of my own labor, too — the shop tanked it and did the bores, and fitted the bearings, then I took it back for assembly. I really like the responsiveness of the Commando and I think it would be a blast in a light car with a manual trans, total power numbers aside. But the easiest way to get 30 more HP might be to put high compression pistons in a 318, with the 273's intake and carb. Cubes are cubes.
Another thing is that the closed chamber 273 heads are getting really scarce on the ground. They often had casting porosity issues, and they crack very easily. I'm on set #5 — not that I actually installed that many, but I have bought several that turned out to have cracks.