cam for a turbo motor?

[r.barn]

I'm not sure how familiar you are with turbos, but the T76 has a fairly high A/R ratio. It's 0.96. That's the ratio of the area of the turbo housing to the radius from the center of the impeller. Turbos that have a ratio close to 1.0 are intended for high RPM use. They will spool up slowly due to the slower gas flow through the larger housing. This may be what you're experiencing, assuming it's the cam. Your cam has plenty of duration.

Yeah, but he's running a 408ci 6.0L motor.
A T-76 should spool up nice even with large A/R with all those cubes

1.0 A/R is intended for high rpm on small inline 6 motors (ie Supras)