Edelbrock LD4B - what's the operating range?

As said, it depends what you want to use it on. On a small head 273/318 it will be strong with a 6500 or so shift point if it's cammed right. Just incase you want to go higher with a small engine, the much hated "Torker 340" with it's medium port size will add another 1k or so. :)