anyone using one? experience-good/bad/ok? i have
one that a friend said i could try. any info is
appreciated. thanks.

I have one on my small block. Only ran it one season so far but have to say I love it so far. Awsome street carb as far as I'm concirned. A double pumper has a slight (possible) advantage on the track but you have to be bang on as far as size and jetting for it to work for you, so I have been told. Whereas the vac secondary is far more forgiving if slightly mismatched on sizing as it will only give the engine what it is calling for. If you go too big with the vac sec carb you might loose a little low end response. Of course this is what I have heard and I can't say I have personally experienced this. The only thing BAD I have heard is the see through site plugs in the fuel bowls they seem to go soft and can leak all over the engine resulting in burning your car up. Mine seem good so far but if Holley (or someone) dosn't come out with a fix soon I think I will be safe and remove mine for the brass ones.
One more thing on sizing I have heard that a double pumper mismatch on the big blocks isn't as serious as the small blocks.
Try it how can it hurt? And good luck! - Barry