Mate there's not a whole lot of info on the edelbrock heads as most do tend to use AFD or CHI's.
But in saying that if you have got your heart set on the E's I cant see too much trouble in getting 400+ from them with the right cam and carby.
I cant find any flow figures for them but I would go a little bigger in camshaft than the one you got listed.Comp Cams Online Catalog
Look at the comp XE274H
And yeah your headers will fit