And with an A3K, that's all he can support, as far as air flow goes.
Without using nitrous, any more than that and the temps will go through the roof.
You can make 500+ HP on a stock turbo, but the temps are TOTALLY uncontrollable and the power is good for nothing but the dyno.
The A3K by itself is good on stock to lightly modified trucks, but he's way over fueled for it.
And he's running a Juice w/ Attitude that already tends to run hot and doesn't increase the RPM range, so he's pretty maxed out right now.
I'm willing to bet that with his current setup, he's already into the mid 1400's for EGT's.
Even upgrading to that new cam, springs and pushrods isn't gonna give him an big gain because he's not extending the RPM range, which is where you see the gains with the cam. You'll get a little faster spool, so you'll see the torque a little lower in the RPM range, but the peak power and torque won't be extended without running a tune that ups the RPM range.
Sometimes more isn't more, it's just more.......know what I mean.