Insignificant part deep in the carb and not even shown in the exploded carb rebuild kit diagram or Holley exploded diagram (I only knew it existed because of a passing reference in the '56 FORD manual). I was looking for replacement idle screws and found them only on Mike's site; looking further I found this nylon ball check accompanied with an accurate description of its purpose which confirmed that I needed it (this ball was missing on my teapot carb, probably lost and overlooked in a previous rebuild). It was Mike's description that sold me on this (I bought other parts, as well). Prices fair and shipping ($4) reasonable (and fast via USPS). Mike is available via toll free number for technical questions.
Reviewed by: Bob from Niantic, CT on 12/24/2019