It would work. 300+ horse depending on the cam. Just guessing. The 273's small bore is where it chokes. A lot of power comes from the heads with big valves and free flow. You can only fit a bit larger than stock valves in the small bore with out notching the block. It can be done. Go ahead and try and record the procedure. Make sure you either dyno it or take it to the strip so we can see the power levels. I have followed a few members here that have built 273's but they either didn't finish them or never got any horsepower readings. No real good reason to bust your pocketbook to get 350 horse when you can do that fairly easy with a 318 or even easier with a 340.