Allstate carburetor

I got the 670 HOLLEY STREET AVENGER 80670. It is $310 shipped.
The ad reads:
This is completely remanufactured with non stick gaskets, 6.5" power valve, NEW electric choke, and vacuum secondary diaphragm, accelerator pump, floats and needle and seat assemblies, clear sight plug screws. Carburetor will come with a new mounting gasket and instructions on how to make the final adjustments. This carburetor comes ready to run. ACFI Remanufactured with updated calibration to eliminate inherent OFF IDLE STUMBLE. Many have experienced the off idle stumble with the Street Avenger series carburetors. We have solved the mystery. Don’t ask us because we won’t tell you how or what we’ve done to fix these pups. It has taken many hours of R&D. Now this is a much more improved unit. This is BETER than a NEW one and has our ACFI BRIGHT ZINC FINISH
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