Please help with performance problem

We went to the track with our 23t altered and were only running around 5.0 in the 1/8 at 140mph.Our old combo was a 527bbc with a old bowers blower and was running 4.50s at 155.The new combo is a 572,11.1 dart 380s and a hi-helix 8/71 40% underdriven. We run 34 degrees timing and i sent the fuel system out to be flowed.The car has a powerglide and 3.73 gears.Its very discouraging with all the changes and id appreciate any advice.