CMC car dyno question

Last year I converted my speed density '86 Mustang CMC car with a '93 Cobra motor to MAF while completing an engine rebuild. Both last year and this year, the dyno shows a drop in power around 3,700 rpm and struggles to recover. I dont notice this on track as my lap times are similar to years past. While on the dyno last year, we did need to replace the IAT and water temperature sensors. We also purchased and installed new fuel injector harnesses as the tabs on a few were broke under the intake.