Torque specs › Small block Chevy › Head bolt torque specs and sequence
Gen I, cast iron heads, pre-Vortec, stock hardware.
Small block Chevy head bolts take 65 ft-lbs, reached in three passes of 25, 45 and 65, working from the center outward. Use thread sealer on the bolts that enter the water jacket, and oil on the rest.
Seventeen bolts per head: four along the intake side, five in the middle row between the ports, eight along the exhaust flange. Work from the center outward, running the full pattern at each of the three steps. The three bolt lengths group by row: every exhaust-side bolt is short, the two outermost middle bolts are medium, the rest are long. Each must return to its original hole.
| Hardware | What to do |
|---|---|
| Stock bolts, light engine oil | The condition the published figures assume. Use the figure as printed, with the thread prep noted above. |
| Stock bolts, dry threads | Published figures assume lubricated threads. Dry, more of the effort goes into friction and the bolt ends up with less clamp load than the number implies. Prep the threads as specified, then use the standard figure. |
| Stock bolts, moly lube | Moly cuts friction, so the same wrench reading produces more bolt tension than the figure was written for. Using the standard number with moly on the threads over-stretches the fastener. Use the lubricant maker's correction, or switch to engine oil. |
| ARP bolts or studs | Do not use the figures on this page. ARP fasteners run at a different clamp load and their torque is tied to their own assembly lube. Use the sheet in the box, or look up your part number. |
| Source | Published figure |
|---|---|
| JEGS | 65 ft-lbs; oil for blind holes, thread sealer for water jacket holes |
| Summit Racing | 65 ft-lbs, stock-type bolts with light engine oil on threads and under the head |
| TorkSpec | 65 ft-lbs, 25-45-65 helical sequence |