2019 ARP Catalog

22 FASTENER TECH Today, there are literally dozens of different cylinder head and engine block combinations for the more popular applications, and new offerings coming out all the time. It is virtually impos- sible for ARP’s engineering staff to obtain detailed information from all of these various sources, so it may be necessary for cus- tomers to calculate exactly what they have so the correct cylinder head studs or bolts are used. Whether it’s a small block Chevy engine or a Honda VTEC, the procedure remains the same. The illustration below shows the nine different variables that come into play when determining the proper fastener for a particular position. Many cylinder heads have different column heights, etc. at various positions, and additional variables come into play when using aftermarket engine blocks (some of which have blind holes for attaching the heads that are shallower than OEM). It is therefore critically important that you determine exactly how many different bolt/hole combinations exist for the cylinder head installation. GETTING THE CORRECT ARP HEAD STUD/BOLT FOR THE APPLICATION CYLINDER HEAD/BLOCK CROSS-SECTIONAL DATA You must have the following data: A. Depth of cylinder head counter bore_ ________________ B. Diameter of head counter bore _ ____________________ C. Column height (net thickness of head) _______________ D. Diameter of bolt hole in head ______________________ E. Head gasket thickness (uncompressed) _ ______________ F. Depth of counter bore in block _ ____________________ G. Length of thread in block _ ________________________ H. Depth of hole from surface to bottom _______________ I. Thread size and pitch _ ____________________________