Like what Fast says, I think of a street combo in terms of leverage:
Heavy/tall gear/tight converter vs engine output, admittedly a gross simplification, but logical to me.
In a way, it distills to Velocity vs. Volume, though the curve for either needs to be considered & dealt with.
Examples: big ports & cam like say a '69 Boss302 were a bit clumsy, and my Hemi 4-speed RR really liked more gear (4.10 vs 3.54).
My little 292" SB 4-speed '57 Chevy from WAY back in the day flat left on everybody, every time, on the street. Big motors were a challenge near the top end.
Though today we'd laugh at how small everything was on/in that motor, it had port velocity.

I thought the not-really-a-950 deal had been addressed by Holley - should be 2 different part #s, I think.
The annular AVS on one of my RRs is cleaner & more responsive than its original AVS, though I suspect the original needs fettling.