I have used both the B and RB versions and still have them.

I have used 650, 750, 850 and 1000 4150 carbs with them and always found them to be a very driveable kind of a piece
that fit under most hoods.

performance wise, I remember....

The B version was down somewhere around 18hp at the wheels compared to a Victor on my 451 combo, not including
everything I picked up with carb spacers which was pretty significant.
Considering how much taller and newer the Victor is, and considering the Holley manifold was probably designed for 383ci,
that is not bad at all. The best I ever ran with the 'B' holley st dominator was 11.24 at 117.3.
As the intake manifold that helped me get kicked off the track for not having a harness or roll bar, it will always hold
a place in my heart lol.

Back when I ran 12s, the RB version was within about .1 ET and same MPH as a Performer RPM with the same
carb and no attempts made to optimize anything, so the test may have not been totally fair. I just threw it on and adjusted
idle mixture. The RPM felt stronger down low and was a little more responsive in part throttle driving as you'd expect from a dual plane. However the RPM is quite a bit taller and won't fit as many cars as easily. They both ran 12:5's at like 106.

They're pretty good pieces. I won't sell mine until I'm convinced I won't want to use them again later.