273 or NOT 273?
The 360 would be a good choice. I mentioned the 318 because some compared the 273 4 barrel to the 318 2 barrel which is a unfair comparison because the 273 4 barrel has more cr and more cam. The 273 is limited by its small bore size of 3.625" compared to the 318's 3.910" which is a .285" difference. If the 318 were to have the same cr and cam as the 273 that would've been a better comparison. That's why I mentioned the 318. The 440 would be good, but there's the extra weight. I think that a 408 would be a better choice over the 440.