Can't help much on boost pressures,

 but if you have this style of fuel injection pump; then your fuel pressures will probably be around roughly 14-18 psi at Low idle, and probably wouldn't be not much higher than 32 psi with engine at "High idle" (full throttle).

If this style of fuel system got up to 40 psi or higher; I would suspect there might be a problem with the fuel return orifice or plugged fuel return line.

(3306 PC engine 2.jpg)

(caterpillar-3306-pc fuel system 2.jpg)

3306 PC engine 2.jpg (81KB - 92 downloads)

caterpillar-3306-pc fuel system 2.jpg (109KB - 115 downloads)

Did you see the original poster mentioned 3306 PC engine?

You copy and pasted 3306B DITA specs [0T7953] using an "Air-to-Air charge cooler", and a 300 HP rating, so they aren't going to be correct. {different fuel system, different fuel transfer pump, different pistons, different turbo, different cylinder head, different nozzles; and probably different camshafts, etc.}

I assume you got the specs, here: (almost 1/2 way down, on this page)

http://www.cumminsforum.com/forum/general-diesel-discussion/63129-3306-cat.html

Fuel pressure sounds fine.

You'll probably have to call the CAT dealer, for any accurate turbo boost numbers.

{Heck, a properly running 3406B model, can be anywhere from 11 psi to roughly 24 psi or so = it all depends on engine specs and HP models. It is such a large range, a person can't accurately guess for a boost spec}

 PLUS, in a trucking application, there is a +/- spec of 15% to the actual factory test spec boost numbers. Note: I believe, heavy equipment might only be +/- 10%. {Semi-trucks have a greater variance, because CAT doesn't control all the inlet and outlet bends and curves and lengths of piping, that can alter boost numbers, due to the airflow "plumbing" of exhaust and air cleaner piping}

If a person gets incorrect info, and makes decisions using that incorrect info; you could be wasting a bunch of time and money searching for a possible problem, that doesn't even exist.