Do block huggers effect hp

I have Sanderson DD7 headers on a built 318. They have 1.5" primaries and a 2.5" collector. I have not run a long tube header on this motor but I can tell you it was like day and night with the manifolds and the shorties.

https://www.sandersonheaders.com/sanderson-dd7-header-set-for-small-block-chrysler-engines.html