I have several things to note.....
A/F ratio shows it's very rich.
Total timing is about 10° too low. Total timing on a 428CJ should be 38-40° total.
Oil pressure is very low, I don't think I've ever seen oil pressure that low. A standard volume/pressure oil pump in an FE will usually have 65-70 psi in the rpms you're running. I would be concerned that a galley plug or something was left out.
Nothing wrong with the valve springs. The cam is just very small for what you have. With a 428, factory heads, factory intake, 9.8:1, and a hydraulic flat tappet with 227/229 @ .050" duration, 110 LSA, and .540" lift, I see 420-425 hp here at 5500 rpm, with 450-460 lb-ft.
It's also a 3.980" stroke.