Cost and availability. I can source a LS1 with trans for $2500 or so. I wont have to swap cams or timing covers. I can also get the wiring I need and PCM for $700 or less. Compared to the Mustang 5.0 for $4K trand for $1500 and control pack for $1500. To be honest I'm a Hot Rodder at heart, ford or Chevy it doesn't matter to me, its all about getting my moneys worth. If I could make it happen for the same price I would choose the Coyote.