Recommended 4bbl carb for stock 318

The Street Demon WILL a spread bore intake, but ONLY if it has the dual bolt pattern. You do have to use the thin Edelbrock plate to block the secondary bulges so they do not leak vacuum, but that's all. It's only like 1/16" of so thick. No adapter is required. Of course if you want to use the thick 1" adapter, that will work, too, but I think they are cheesy.

And I would have to see drag strip results about adapters ADDING power. I do know that they do move the power band UP in RPM range, but I think it's splittin hairs to say they add power. At any rate, on a street engine, it most certainly IS splittin hairs.