Power advantage between Ford 351, Mopar 340 and Chevy 350??

I tried to find the original article online but no luck. I wanted to see the criteria, they did mention only 1970 econo cars. Was the 1970 Boss left out because of a higher price point? Was the Mach1 a cleveland engine?
Mach1 was a Cleveland. Not all Clevelands were the same.