Hey guys I really could use some advice here. I'm no stranger to engines in general and all things automotive, but embarrassingly I'm getting my a$$ whooped on one of my built NA 540 engines.

Here's a run down of what's going on and what I've tried.
-Engine is burning cylinder 2 where its black and loading up, under revs there is a noticeable misfire that's on the 2/4/6/8 bank. Plug the plug after running and it's cooler then the other plugs and black.

Tried plug wires / plugs / swapped caps / swapped carbs from other engine / replaced the lifters. Engine has aluminum heads, Victor Jr intake / Holley 950 / constant fuel pressure at 8psi / compression is 135 across the board / leak down shows some blow by into the crank case but approx 15% none thru the valves / Gil exhaust manifolds / bigger cam roller motor / MSD distributor and box.

My questions are, can an internally leaking exhaust manifold on that bank cause the issue of misfire / can the msd ignition cause a single cylinder issues / or what in the heck should I do check next? Any advice would be emmensly appreciated. I'm really at a loas and tired of swapping parts and getting a plug that loads up and starts missing. The boat will ride well but at upper throttle trying to push the engine it's about 500rpm off max Rpms "5700" at WOT due to the cylinder misfiring out.

Thanks