Sorry... I actually can't 100% recall the intake spec, but from memory they are both square bore... Interested to know where you're heading with this though!?!
The standard Edelbrock performer is a spread bore intake. There's no need for that 1" spacer. They are almost always a point of contention for vacuum leaks. This is all you need. Edelbrock 2732 Edelbrock Carburetor Adapters | Summit Racing
It seals around the outside of the secondary barrels properly. That may or may not be the issue you have, but I sure wouldn't be running a spacer like that when it's not needed.