I was trying to find that gnx carburetor mount you have but could never figure out what it was called - to initially do a draw through setup, but instead i opted for blow-thru and so far I'm ok with it.
If you were looking for a GNX one, that may have been part of the problem. GNX was the last year ('87) of the 'black' cars, and the g-body in general. The ones that got the draw thru carb plenum were 1978-82 turbo regals