Re: 427 TUNNEL PORT
Boy is that an understatement! The tunnel port head never came on a production car unless you call the 6 GT40 MKIVs a production car. The heads were over the counter only. C7OE 6049-K. The head is hampered by the "conventional " 427 exhaust port.
The SOHC never ran a Nascar race, it was not approved for competition when presented to Nascar leaving Ford with a few hundred of them which were set to Holman Moody to be sold off.
The tunnel port was Ford's designated replacement as it "fit" into Nascar's rules. They were allowed dual fours and a weight break over the hemi. That allowed the 427 to be competitive. By late '67 Ford set forth on building the ( then named) 429 Nascar engine and it WAS as powerful as the Chrysler hemi. ( the street version was easily out run by a 428CJ Mustang as previously mentioned). The tunnel port head wouldn't ( in the day) go beyond 1,000 hp , where the cammer and Boss were capable of 2,000+ on nitro.
Ford engineers were constantly reworking the tunnel port head to improve it. Port configurations , "air foil" pushrod tubes and a host of other mods are in my SK book listings. IF it were "the answer" it would not have been dropped after two years of use. It was great in it's day but unfortunately time marches on.
The 427 side oiler was a direct result of the SOHC engine program. When the C5AE block patterns were created , they were made so that "top oiler" or "side oiler" configurations could be machined into the casting eliminating the top oiler block patterns. Marine and industrial use 427's got the revised block with top oiler machining and marine engines got brass core plugs
Experimental Ford parts collector.