A1 Automotive Machine, LLC

Apparently as the story on the internet goes these 379 blocks are rare

Today’s project: installing O-rings in the deck surface of this Honda H22.

1.940/1.600 valves roughed in on a set of 305 HO heads!

From early 1960s Buick Nailhead cylinder heads through mid-2000s GM Vortec castings, factory deck surface finish quality showed little real improvement, as evidenced by the common “zebra striping” caused by aggressive production feeds, uneven insert height, tool wear, and casting hardness variation. These finishes were considered acceptable because composite gaskets masked the inconsistencies, but they often fall short of modern sealing requirements. Current CBN and PCD tooling correct these issues by providing superior edge stability, minimal tool deflection, and consistent cutter geometry, allowing slower, controlled feed rates and repeatable surface roughness values. The result is a flat, uniform deck surface with predictable RA numbers suitable for MLS gaskets, eliminating the sealing risks inherent in original production machining.