| Diagram | Fig. 10 — CLUTCH · ref 18 |
| Subsystem | engine top |
| Listed in parts books | 1963–1970 |
Adjuster lock nut
Lock nut for the tappet adjuster stud, used to hold valve clearance settings in place.
GS662 is a lock nut used on the tappet adjuster, the threaded stud that sets valve clearance up at the rocker arm. Once you've set your clearance with the adjuster, this nut cinches down against it to keep the setting from creeping as the engine runs and vibrates. It's a small, plain flat nut, but it's the piece that keeps a careful valve adjustment from drifting off the moment you close the timing cover.
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This one turns up across a long run of cylinder head and clutch figures in the parts books, with a thread that matches the tappet adjuster stud it's paired with. It also carries the 60-4264 / D4264 number in some catalogs, same physical part under a different reference. Worth keeping a couple of spares on hand since they're easy to lose or mangle with a spanner when you're chasing valve lash.
The catalog spread on this one covers a wide range of cylinder head and clutch listings from the 1960s, but we don't have it tied to one specific model here — if you've got the head off and need to match thread and fit, bring the old one in or give us a call before ordering.
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