[bmalone]

Tunnel-port was an over-the-counter option back in '67 and '68 (for the 427) that consists of an intake and set of heads. TP heads must go with TP intake and vice-versa. It is called tunnel-port because the pushrods go right through the intake runner. This means that for the intake side, the mixture runs straight into the combustion chamber (no bending around the valve as is common for other engines).

The exhaust arrangement is tradional in all other senses. That is why this is not a hemi engine (valves not opposed for one thing).

The size of the intake ports is enormous--nearly as large a diameter as a soda can. They flow like gangbusters, and that is what they were designed for (high-revving)--very successful in NASCAR and 1, 2, 3 in Le Mans. Mine redlines at 6500.

Keep in mind, this was back in the sixties, and there are certainly other ways to skin a cat these day.

There were three manifolds made: 2x4 single-plane, 2x4 dual-plane (Le Mans), and 1x4 single-plane (360 degree style).

In a heavy car, one might give consideration to using the dual-plane. But, for a Cobra, you will have no streetability issues if running the single-plane (but it is a wives' tale, anyway).

Mike does some outstanding work and I believe he took a single-plane and converted it to EFI.