Thrust problems with two step in Stock

[GTX JOHN]

My son and I have both have lost thrusts on our Stocker
that run two steps.

Our SS cars have never lost the thrust. Many of our engines
have the same crankshaft builder.

Is there something about how the works on a brake petal
that is different than the way it effects the engine on a brake.

That does not make any sense to me, that there would be any difference
as both ways they operate under similar load.

It seems to happen about the 100 to 125 run point on the stockers.

Do I need to find a new crank man, I have been using the same guy
for last 30 to 40 years?

Does anyone else have this issue?

Appreciate any Feedback!