Yes I think Ordy says it best. I was just showing a Square bore manifold,
The 2156 is both a Spreadbore manifold for Qjet's, if you want to use a square bore Edelbrock Carb's they make a square plate to bolt down under the carb., I ran a 2156 and a 1406 for 13 years with no air leaks.
The 9790140 is a great manifold too, I bought one to keep in storage, I plan on putting a Qjet on top of it, do not sell yours.
It was said a 68 9790140 shouldn't be on a 1974 engine, the crossover leaks out on the 1974 engine, thats why Edelbrock"s 2156 made the flange wider there to block it off, if you look at the picture.