Sorry, I thought I answered your pm, the PM I answered was from someone else and I assumed

The manifold I have left is a peanut port (truck heads) it is a Edelbrock Performer 2.0 and in really good condition, the only negative is there is some signs of corrosion on the rear water passages which is pretty normal for a boat, more than useable, but like I said small, round ports, be more than happy to put up a pick. $100. and its all yours.
BTW I emailed the guy with the GM piece, will let you know the response...I'm curious myself.