This is a marine application and the overlap is about as high as I can run with the exhaust outlets under water. The cam is a comp extreme marine 284 hydraulic roller. 230/236 @050 .557 lift.
Provided the cap looks good then you’ve got the ignition covered.
I’m afraid we might be overthinking this whole deal. It’s a big block Chevy. Then I looked at the pictures, because isn’t this an asymmetrical intake port engine with the long and short intake ports that require weird intake tracts like calliope injection? Aren’t these engines known for needing the carburetor jetting staggered to get consistent plug readings?