Hello,

During the 70's, Volvo got a batch of soft cams and the lobes were prematurely wearing.

So Volvo did a recall.

During the recall, Volvo discovered that the torque specification in the manual was too high at 90 ft/lbs because mechanics were breaking off the threads on the new replacement cams.

The correct torque is 75 ft/lbs.

Sounds like someone did not know of the correct torque specification and drilled and tapped to save the cam.

I have plenty of good used cam nuts.

BTW, the proper sized socket for the cam nut is actually 36mm nut, which is common as it is the same size as a VW rear axle nut for the old air cooled models.

I am not sure about about the thread pitch.

"D" cam is an excellent cam for stock motors and I use them regularly in my rebuilds, but beware white box camshafts as they are pieces of s*&t.

I have copies made as Volvo wants over $700.00 for a camshaft.
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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90501