Interesting I put down 349 hp and 410 torque at 15-16 psi my mods are TE-60 with garret exhaust housing, Th350 trans with Redneck 3000 converter, msd 50lbs, ebay fmic, stock cam, heads, and 2 piece 3" downpipe with ported elbow my fuel was E-85 and timing was 21 degrees I believe. My car ran a 12.04 @ 111 mph with a 1.711 60 ft at 18 lbs would have been faster but got knock on that run from a loose downpipe. I'm using mt drag radials at 15psi and only 1 air bag. My torque curve was much more flat than yours I will see if I can find my dyno sheet for you, I haven't redyno'd it at 20 lbs so not sure where my car would be at with that level of boost for an apples to apples comparison.
Your power seems like it comes on pretty high in the powerband, maybe you have a boost leak and your air fuel looks pretty funky.