Overhead camshaft engines are commonplace today but Detroit has been tinkering with OHC V8s since the ’60s. This is our list of 5 monsters never sold to the public.
1968 Ford 289 SOHC V8
Ford built three experimental 289 with a unique single overhead camshaft design that features a cam located in each of the cast aluminum valve covers (instead of on top of the cylinder heads). The lobes of each cam activate the cast iron rocker arms that open each valve. In the original camshaft position within the engine is smooth shaft whose role is to drive the distributor as well as the two overhead cams. The purpose of this project was to raise the maximum engine speed and with it peak power. The OHC 289 produced 300 HP at 6500 rpm.
Ford considered offering the SOHC conversion as a kit. But as the stock HiPo 289 already made 271 hp, and Shelby was getting 306 hp with bolt-on parts, it was deemed not worth pursuing.
Oldsmobile W43 DOHC V-8
As part of the development of the Oldsmobile 455, Olds engineers wanted to take the design of the engine as far as possible. The ultimate version added a set of dual overhead camshaft cylinder heads to the mighty engine. A gear drive supported by roller bearings in an aluminum gear case at the front of the motor spun the cams, while a driveshaft was used in the standard camshaft position to transmit motion to the oil pump and distributor.
Toward the end of 1969 engineers dyno tested the DOHC W43, built with a very racy12.2:1 compression ratio, and recorded a very flat (and fat) torque curve. Peak power Olds engineers recorded was 700 horsepower at close to 7000 rpm.This was achieved using the standard cam profiles for the W43, ground onto separate intake and exhaust camshafts. At that point, no development had been done to optimize cam specifications to match the breathing of the heads.
But on January 1970, General Motors President Edward N. Cole announced that all GM divisions would lower the compression of their motors so 91 octane unleaded fuel could be used, and development stopped on the DOHC Olds.
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