For those of you interested in subjects like this check out this web site.
http://users.erols.com/srweiss/tablehdc.htmThe Tunnel Port 302 cylinder heads did receive much negative press back in 68 but they really aren't the main culprit in the Ford racing failures that year.
For one thing there is no way that they flowed numbers that Ford had published. In fact they were around 250 on the intakes.
The iron Boss 302's stock were actually a little better out of the box BUT if you follow some of the magazine articles on the race prep for the B2 heads, they were getting epoxied down quite a bit to make the rpm usefulness scale.
It may just be that the C head was more adaptable to race prep then the TP was.
The only head of interest to me that Weiss has not tested is the GT40 iron head from what I can see. Even the Gurney head is on the list of testing.
All in all this is an interesting read and should answer many questions as well as probably shocking you as to how bad stock heads were out of the box then especially
considering what today's aftermarket heads do.