The tunnel port and single overhead cam (SOHC) are always pulled to the side in discussing FE cylinder heads, due to the dramatic differences in layout and design. The high-riser head should also be included in this list, given the noninterchangeability with common FE components. All three of these are developments from Ford racing programs, and were never in volumeproduction cars. Only the high riser made it into vehicle production at all; the others were over-the-counter race parts only.
As previously mentioned, the high-riser head has a dramatically taller than the usual intake port, and requires quite a few unique components in order to be installed. The intake manifold is different in both port design and valve-cover mounting rail position and angle. The rocker stands are considerably shorter due to the raised upper surface of the head, again done to accommodate the ports. These characteristics mean that none of the currently available high-volume-production aftermarket intakes or rocker systems will fit. The only aftermarket intakes for these heads come from Dove—a specialty supplier dedicated to low-volume FE racing parts.
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Tunnel-port heads are another completely different cylinder head that came from Ford’s racing program. Never installed in any production engine or car, these heads were an effort to address the airflow needed in continuous high-RPM-racing applications, such as NASCAR and LeMans. Rather than trying to snake the ports around the pushrods as done in conventional heads, Ford simply put the port where it wanted it and ran the pushrod through it inside of a tube. The ports themselves are very large and rounded in shape. The intake manifolds for tunnel-port heads are unique in port design and bolt pattern. They are very interesting parts with a wellproven record of racing success—but not parts you are going to find in the average swap meet or street car on a Friday night.
The SOHC 427 engine (the socalled Cammer) was perhaps the most exotic package that actually made it into production during the muscle car era from Detroit’s “Big 3.” It was never sold in cars, but was available over the parts counter—a 1960s crate engine. The huge cylinder heads with single overhead camshafts are the visually overwhelming feature, but the package entailed a lot more than just those. With hemispherical combustion chambers, a solid-roller cam mounted in each cylinder head, a unique multiple-chain cam drive, plus specialized intakes, front covers, valve covers, and valvetrain, this should almost be considered a completely different engine built around an FE block and crank. The SOHC has recently seen renewed interest, as several specialty suppliers have begun reproducing the components needed to build them from scratch.
Written by Barry Robotnik and Republished with Permission of CarTech Inc