"Comp"..vibration dampner?

My 3.8 E type vibration dampener has the word “COMP” stamped on it…what could this mean?

Competition at a guess.

My 140 (C-type head) also has that stamping.

My belief is that it is made to withstand higher RPM’s than the standard one which is made of cast iron I think

We have had exhaustive discussions on the various XK engine torsional dampers. You should be able to do a search and find out anything you need. My recollection is that the dampers of certain models were all stamped COMP.

What’s “Roger Down Under’s” last name?..he has posted much info on this…search the archives.

Composite at another guess

That sounds most reasonable

From the XK120 Spare Parts Catalogue:
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From the XK140 SPC:
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Service Bulletin 95 says the C5809 competition damper is specially tested for operation at high rpm.
Cost was 6 pounds 15 shillings.