I don't entirely buy that. The HD manifold has an outlet that could potentially flow more then the EFI dual outlets. But the rest of the HD manifold is still a log style manifold. The EFI manifolds are a better design. And the outlets can always be enlarged by doing some porting.

No matter what you do to the HD manifold, it's still a log style manifold. It's not a direct replacement for the standard carb manifold. The heat riser is slightly different and it doesn't have any shut off valve in the heat riser like the standard carb manifold does. The only reason I see for choosing it over the EFI manifolds is if someone really doesn't like the looks of the efi manifolds. I know some guys want to keep the stock look. Or if making a turbo set up. I know the HD manifolds can be modified for that.

And to add to the above the HD manifolds are more expensive. So if I was sticking with manifolds the efi would be my choice. But I'm building my own headers.

And as far as headers go. There is a way to help with the heat problem with headers, but it's not cheap. Ceramic coating the headers can cut under hood temps down by a lot. But you still can run into starter issues ( just more of a pain removing and installing the starter ) . And most of the available mass produced headers have thin mounting flanges that can warp.