I need to find the special torque wrench tool for

Cylinder head nut torque extension? 1/2" drive x 11/16" box end wrench size was Case p/n CAS1257. Photo is the same extension, Snap-on p/n S8663B.

Joe

Photo from a "george md" post. Note that drive extension must be the same length as the driven extension (no offset).

Another alternative is the older style bending beam torque wrench. The socket wall may have to be ground down to clear the pushrod tubes.

Joe

Take a (cheap or whatever) 9/16 and 11/16 (12 point) boxend wrench and weld a piece of steel (pipe or whatever) in between them; to form a sort of a C.

Put the 11/16 on the head nut. Hold the 9/16 centered above the head in the same position, cut the pipe to fit in between, out beyond the side of the head. The 9/16 will fit tight on the 1/2 sq drive of your torque wrench.

The ext used to be common back when cyl heads required retorque after so many running hours and one did not want to pull the rocker arms. They were generally called "under rocker arm ext" in the marine industry.

Another option is to buy a box end ext similiar to a crowsfoot. I think most tool suppliers can give you the offset calculation or do a search, it will be avail on the net.

Joe