The only way to make more power is get more air and fuel in. Port work in a diesel is critical to the motors ability to put more air in the chamber. Boost is only a measurement of restriction and not the amount of air capacity you are putting in. When F1 cars ran turbo’s they were restricted to 1. 5 bar, or about 21 lbs of boost the made 1100 to 1200 hp on 90 cid.
The goal here is pounds of air in, not pounds of boost. Under high boost all you do is heat the restricted air and make it less dense, thereby reducing the true amount of air you are actually putting in past the valve. I have seen the more port work and the more cam timing you put in these motors, the less restriction you have in the intake track, resulting in less back pressure, and cooler air. Big boost numbers are something I would not brag about. If I was building a street motor, I would while the head was off getting o-ringed, have a pro port and work the chambers and do a competition valve job. The 24 valve head picks up 15 to 20 numbers with just a bowl blend and competent multi angle blended valve job.
I have some of the best turbo’s Ken builds, the same place Mad dogs gets his. I make good power, and the boost levels are no where near what they claim. The more I work the heads and progress on cam design conferring with John Russin and Brian Block the faster it goes , funny thing the boost keeps going down ,and the truck keeps going faster with cooler air. There are several people in the country capable of porting heads correctly. As to loosing low end, that is absolutely wrong, that’s only in gas engines, as there is no fuel in the intake track or chance of reversion in a boosted motor. The heads are plenty thick in the areas to hold any thing most 500 to 800 hp motors are using for boost. One of the fastest single trucks out there is John Russin’s street truck. He is a stanch advocate of head work, but get you wallet out he is not for the faint at heart.
If I was laying out a good fun street truck, and everyday driver, it would be with an emphasis on head and cam work with a good single charger, like the B104 or B1 , the head work will do the same as a big charger , IE cool the intake charge and cool EGT’s