lookin at a set of lightnings. I have the gils on hp500 with silent choice. Lightnings are the standard header and removing silent choice. I dont believe reversion will be a issue with this set up.
However i plan on putting on a set of afr 305 heads and i have a custom ground cam by rmbuilder that i got of a oso'er that had same set up. cam is in225/ex231 582/597 lift on 112.
(numbers are off top of my head, may not be exact but are close). Would reversion be an issue? would the reduced water header be a better choice

I have Lightning headers on my 522, my cam is 242/252 @ .050" and .623/.611 with a 112 LSA and no problems. The Lightning's are taller than stock which helps keep water out of the cylinders.

You will be fine! I have Eickert headers and am running an RM Builder cam that is 234/241 dur .63/.615 lift with 112 lobe sep. I also ran this cam with standard length Stainless Marine Manifolds.

lightning makes a header for silent choice if you want to keep it...

where do you boat? Be careful of corrosion if in salt. He makes to different kinds.

ohio river and ky lake, and loto when i can. NO SALT