Doubt it's a heat soak problem with the engine running just that short amount of time. The pump is in its born location. Shouldn't get hot there.

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