HOME                                                      INSTALLATION INSTRUCTIONS

ARP HEAD BOLT AND STUDS INSTALLATION

Head stud and head bolt kits are used to improve clamping of the head to the block.  Improving the clamping force reduces the incidence of blown head gaskets.

 Early Y-Blocks were assembled with average quality head bolts. These were upgraded late in production to Grade 8 fasteners. This reduced the number of blown head gaskets but there is still room for improvement.

Our head bolt and stud kits utilize ARP fasteners, which are a vast improvement over production Y-Block fasteners. These are 8740 alloy with 190,000 psi tensile strength.

 Either kit is a direct replacement with no modifications necessary.

 Y-Blocks use longer bolts at the ends of the upper row of bolts due to the recessed threads at the block dowels. There are 4 bolts that are ¼” longer that must be installed in the end boltholes.

 ·        Chase threads in block with a 7/16” X 14tpi tap to ensure threads are clean.

·        During installation take care to install the washers with the internal bevel toward the bolt head.

·        Studs can be tightened in block then backed off ¼ turn. Some builders prefer to torque studs in block.

·        Square edge of head gasket must be installed toward the front.

·        Always lubricate all threads, nuts ands washers during assembly. This will ensure that the force required to turn the fastener is being used to tighten it.

·        The best results have been achieved with multiple tightening of the heads. After the head is torqued to spec, loosen all fasteners and repeat the tightening sequence. This should be done at least 3 times. It has been found that if only tightened once the fire ring surrounding the cylinders might not compress completely resulting in coolant leaks upon initial start-up.

                                  TORQUE SPECIFICATIONS

 Tightening sequence:                      9      5      1      3      7

                                                         10     6      2      4      8