10/22/2026
⚠️ Something we’ve been seeing more frequently on older Holley carburetors…⚠️
Over the past couple of years, we’ve started noticing what appears to be deterioration in certain Holley castings from the early 2000s.
Take a close look at the first two pictures. You’ll notice small cracks forming throughout the castings. We’ve encountered this in metering blocks, fuel bowls, and accelerator pump covers.
These aren’t just surface cracks, either. We’ve found them to cause both internal and external fuel leaks, and the metering block pictured here shows evidence of both.
Interestingly, we haven’t noticed this same issue in older or newer Holley castings. We don’t know exactly what’s causing it, but it seems to be associated with a particular era of production.
The third picture shows a casting date code. The “05” indicates 2005, and the markings around it appear to indicate September. Similar date codes can be found on other Holley cast components.
Fortunately, the other components on this customer’s carburetor showed no signs of deterioration, so we were able to replace the affected metering blocks with a new set of our billet blocks and rebuild the rest.
This is exactly the kind of thing we’re looking for during our freshen-ups. Catching problems before they become much bigger issues!
👉 www.siebertperformance.com
