Thats my point exactly: "with all the commando stuff ( The intake, advance curve and springs... whats left?) and 2bbl pistons...260+HP at 5500" imagine all that motors commando stuff (and other parts) on a ~18% bigger 318 short block (like I had, night and day with the 318 block). Like I said on the other thread, there aint much a 273-4 can do that a 318 cant do better.