1999 Ford Mustang Boss 351 Concept Coulda Been a Contender
Ford built this prototype in secret, but now it's seeing the light of day.
Twenty years ago, a small team of enthusiast engineers at Ford had an idea. The company needed a serious engine to compete with the Dodge Vipers and Chevy Corvettes of the world. Ford had a V10, but it was huge at 6.8 liters — and tall, too. That wouldn’t fit in either the Mustang, nor the Ford GT, which was also in secret development at around the same time. So, the perennial teenagers in the performance department got creative.
“There was less oversight then,” said Jim O’Neill, powertrain prototype build leader.
“Could you do something like that today?” I ask.
“Not a chance,” said O’Neill, before he and Greg Coleman, now in 5.2-liter performance engine systems, began laughing in unison.
Those two guys, plus a few more, took the sand castings for the 4.6-liter modular V8s that Ford was using in the Mustang GT and added two more cylinders. That came out to a 5.8-liter (351-cubic-inch) aluminum block, dual overhead cam V10 only slightly bigger than the then-current V8. The engine control computers, which Ford had on hand, think they’re running two I5s since thee V10 computer Ford had only worked with the Triton truck engine. The assembly managed to fit under the hood of a 1999 Mustang Cobra R mule that was stashed in the shop.
