De-Mandated CM870

[AK Trucker]

I've got little over 3k hrs on this motor since it was tuned (which was done right after a infarame) and I feel my EGT is a bit high and not putting out enough power. During a long pull it'll reach 1000 degrees put usually doesn't exceed 950 degrees. Cruising is around 750 degrees.
I'm constantly pulling heavy. Usually over 100k lbs and I'd like to get more power out of her without cracking liners if that's possible.
When I first bought the truck 7 years ago I had it de-mandated and the guy messed with my timing to get more powerout of her and like a fool I trusted him. Long story short I ended up with a cracked number 5
I'd appreciate any helpful advice so I can finally love this motor and stop hating it.