Reply to "Ron (accobra) & all, another interesting intake manifold"

George is going to tell you the same thing I am DT. The ports on the Boss 351 are the same as the Boss 302, and all Cleveland 4v heads.
I think what you are thinking of are the 302 Tunnelport heads. Those are round.
This manifold that we are looking at is the 69 Boss 302 Trans-Am intake. The Dominators mount sideways and you need to use an offset distributor for it.
The size of the carbs added to the problems of lack of velocity through the ports. Valley Head service (I think they later became Falconer and Dunn) solved the problem by closing down the intake ports on the heads to a little larger then the 2v 351C heads with plastic epoxy.
The result was about 425hp at about 8000rpms.
The Full ports produced maximum hp somewhere over 9000, which is around 500 rpms past the engine blow up point.
This appears to be an unported manifold, from what I see.