Scout, I was going through some of the same problems as yourself with high egt's. My truck is heavy and built like a brick.

A couple of months after installation I made an adjustment to the star wheel and full load delivery rate cone under the star wheel. Neither one was "maxed out". This provided ample power and still retained good economy. Did not adjust full power screw! However, Empty truck during warm weather at 65 mph and flat ground would produce 1125* egt pre turbo, 1250-1300 on rolling hils or good headwind. I Would have to slow down on some occasions to prevent possible damage to my engine. Some frustration at this point

.After some brainstorming (this is painfull for me!)' I fabricated a fresh air intake with AEM filter. This produced no benefit until I discovered that the JWAC aftercooler was stabilizing charge air temps at above ambient air temps! I stopped coolant flow to the aftercooler and saw an immediate 100* egt drop. Next I started fooling with the pump timing. About 1mm advance produced a slight improvement in egt but a large improvement in highway power. (NOTE: use your pump timing to fine tune your torque curve for best hwy speed power.) I then advanced to 2mm. Egt's dropped about 50-75* but highway power suffered. Also max boost dropped from 14 psi to 8psi. This had my best torque above my cruise rpm. Dropped timing to 1.25mm advance and added 12cm turbine housing, highway torque is perfect for my gearing and tire size at 70 mph, Egt at 70mph flat road is 975*. Max boost came back to 15 psi. The turbo definitely spools quicker. Before 12cm housing I had 0 boost at 65 mph, now I have 3psi at 65mph. Boost climbs quicker an hills because of the quicker spooling which makes the egt's more stable on hills. I usually only gain about 75* on the rolling hills back and forth to work. Before it would be 150-200*! I havent done any heavy towing yet but light towing (4wheeler and small trailer) worked just fine. I could be happy at this setting but tech guy at Gillette Diesel Serv. suggested a compressor wheel and housing would also help so I have that on order. I will ad this info as soon as I have it. Call Steve at 800-638-4679 and have a chat. 12cm housing shipped was only $145. Be aware my engine will turn 2960 rpm but I never use it. Stock setup would pull all the way to this rpm. 12cm housing overspeeds at 2700 rpm and falls on its face immediately! I seem to never go beyond 2600 except for baseline perf. figures for you guys so this is not a problem for me. Hope this helps.
Carl
1979 F-250 crew cab 4 x 4
4 bta with modified H1C
Cold air intake
ZF S-42 5 speed
Borg Warner 1356 x-case
Dana 60 rear
Dana 44 front
3.55 gears
255/85R16 tires (33.5x10.5)
Hydroboost steering and brakes
Custom 40 gal. fuel tank
Much more later