Muscle Motors indeed did have an excellent reputation at one time. It was primarily because Chuck Senatore ran the place.
He left a long time ago.

69 Dart GTS A4 Silver All steel, flat factory hood, 3360race weight
418 BPE factory replacement headed stroker, 565 lift solid cam
Best so far, low 10.30’s 1/4
1.41 best 60 foot
6.56 at 104.17