Generation IV Internal Engine - Low dyno numbers?

First off let me say I dont care what the car dyno's. I just want to make sure I'm not leaving anything on the table.
Car is a 98 z28 auto. It weighs 3420 with me in it. Mods are as followed
02 ws6 shortblock
853 heads
TRex camshaft
Ls6 intake with slp throttle body
Circle D 4000 converter
4.10 gear
1 3/4 header with 3 in y pipe into what looks to be 2 or 2 1/4 catback with hooker muffler
E85
The car does have 3 degrees of timing pulled for nitrous
It made 359/351 this weekend with the converter unlocked on a dyno jet dyno.
The car has ran a best of 11.98 at 112 with a 1.67 but consistently runs 12.0 at 111 with 1.64 60s all day. This was with 3.73 gears. I just recently did the 4.10s. Do these dyno numbers seem low to anyone? The AFRs were spot on and everything tune wise looks perfect

You need a better exhaust IMO. Especially if it really is 2.25" or smaller. Either go 3" duals or at least 3" into 3.5"-4" single.

You will get more hits if you have this moved to the right section. Either gen 3 internal or dyno section.

you needed to post in the gen3 section but yea the numbers seam low and i agree with thunderstruck that exhaust is way to small

I would say it a little weak. My 98 trapped 116 at sea level with a 230/224 and stock 806's

I just realized this is in the wrong section. I'll move it. And I do agree with the exhaust being too small. I need to change it