OK, we admit it. We haven't been giving the 351 Cleveland enough ink lately. Seems everyone is building the venerable 289/302/351W small-block, which our readers love because they're plentiful and easy to build. That makes it easy for us--perhaps a little too easy.
Ford's legendary 351C middle-block was a back-door surprise for 1970. In 1969, Ford introduced the raised-deck 351 small-block we came to know as the Windsor. It looked similar to the 289/302, but it was a pinch wider, a hair taller, long on torque, and ready to make unrealized power. Then, scarcely a year into production, the 351W had company: the more powerful close cousin with the same displacement in the form of the 351 Cleveland. It's often been asked, why the same displacement from a different engine family? There have been a lot of theories, but so far no concrete answers from anyone who was there to see it unfold firsthand. We'll kick around some solid theories later in this article.
The 351W was little more than a raised-deck 289/302ci V-8 with the same 4.000-inch bore, but half an inch more stroke than the 302. It also had similar cylinder-head castings with slightly larger valves and ports. The 351C's 4.000-inch bore and a 3.50-inch stroke was dimensionally the same as the 351W, but it differed in block design and large-port, poly-angle-valve heads. The large-port heads were designed to flow better at high rpm, allowing the 351 middle-block to make extraordinary horsepower and torque on the racetrack. On the street, the 351C wasn't the powerhouse it was on the track because the oversized ports didn't yield the velocity at low rpm necessary to make good torque. This was certainly true with the 351C-4V and Boss 351 engines. In 351C-2V applications, low-end torque was improved, thanks to smaller valves and ports. But the 2V heads suffered from combustion-chamber shortcomings that caused excessive spark knock and reduced compression.
When building a 351C, it's a good idea to know how to amass the right parts to make the most of your buildup. We're going to show you how to coax more horsepower and torque from a 351C without having to sell the farm.
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