Square-bore vs. spread-bore?

The first picture is the TQ base with a Q Jet adapter. The area to the right won't leak, but the thin line on the left is where it will leak. The second and third picture are the Q Jet adapter on top of the TQ adapter. All of the pictures of the nuts and bolts, and studs are what is needed when you use an adapter on a manifold that only has the 4 carb mounting holes. Picture #6 is the TQ base on the TQ adapter. Picture #10 is the TQ base on the Q Jet adapter. The first set of 4 bolts are 5/16 X 1" socket head bolts with the circumference and the head ground down to fit flush in the adapter. These bolt the adapter to the manifold with just a thin gasket. The studs are 5/16 X 1 3/4" or 2" from Ace Hardware, they are a lot nicer studs that those that are available from Edelbrock, Holley, or any automotive place. When you buy a new adapter you get hardware with it. I've never bought a new one, so I always sourced the hardware from what I could find. You need a thinwall nut to fit inside the pockets on the adapter. Years ago I found that Ford used SAE 5/16 with a 7/16 head, on their carburetor mounting studs from the 60's thru the 70's on their FE motors, probably others. That's the only place I could find them. I'll further explain if needed.