79 35el dead cyl

[floatmyboat]

Hey guys, I have a 35el79a that doesn't have any power under load, I believe it's a dead cyl issue. I pull bottom plug wire, no effect, pull top plug wire kills engine. Bought and installed 2 new oem coils, no change, what next? power box maybe? any ideas welcome, thanks

[boats.net]

Run a compression test first. Check to see if firing on all cylinders, if not then could be power pack.