67 dart stroker hellcat gen3 hemi with twin turbos...

Oh man i feel your pain. I chased a rpm input drop for a year and a half. Tried everything. I got fed up and went back to square one. GROUNDS. I put a ground lug in the trunk and one in the engine compartment. I connected both directly to the battery with 2/0 cable. All grounds go there except the “clean ECU ground which still goes directly to the battery. I then ran 2/0 cable to the block. Both heads and the intake manifold. Problem solved. I never thought a ground could be the problem since everything works perfectly but it had some ecu “glitches” of course Holley was no help. I was so impressed with my fix that i did it to one of my street cars that was hard to start. It totally fixed issues i had no idea i had an issue with.