Just get a 360......hahaha....just kidding. I say yeah go for it. Might wanna get some better rods, and better pull out the ol' wallet if you want some 273 forged pistons. Chances are, your 273 crank is forged steel so that's good.
I was thinking of going the same route, except using a turbo. 273 engines are basically free, and that's always a nice starting point.