Cummins cylinder performance/porting

As my work truck rolls onto 625k km's, I'm thinking a head replacement in the future is coming. Being that I can't leave well enough alone,does anyone know who builds a good ported performance head for CR 5.9?
And what upgrades could be done for valves, springs etc?
I saw a flow # for the 5.9 head that shows 180 cfm on the intakes which seems kida wheezy. I imagine the porting is tough because part of the intake is part of the head.

Ive never been able to figure out why diesel heads are always garbage in the flow department, they could run less boost if they made normal heads that weren't like trying to breath through a straw.

I have personally done a little porting on them but there just ain't much you can do trying to get to the ports only through the chamber side so everyone just turns up the boost.

D&J Precision Machine

What year is your truck?

power driven diesel has there own heads cast look them up on u tube they pretty impressive out of the box un ported. they also offer cnc head porting for them. the heads are cast and are direct replacements

Truck is an 06, only mods so far are stainless port matched exhaist manifold, hybrid turno, and 4" exhaust.