The 302 tunnel port was a poor race motor. They had good H.P. but no torque and you had to spin them to 9,000 all the time. They did not last for a whole road race. That is why Ford lost the 68 Trans Am season to Chevy. Here are some pictures from the Shelby day at the Simione museum in Philly. This car was on loan from Ross Meyers. It is an original Shelby T/A coupe with a tunnel port 302. It is show quality but they still vintage race it.
Neat. Ford offered a revised tunnel port head well into the early 90s through Ford Motorsports. They had cast in tunnels instad of the pressed in pushrod tubes like the original versions, among other small differences.