I have two svt engine tags. i got them when i was part of the svtoa club and toured the niche-line. they are stamped by the engine builders there names are W. King/ Rpm and the other tage has Greg Hollussk/ Dave R. Slater. Are these tags worth anything? I was thinking about putting the on ebay but i am not sure. Does any body have any idea what i should do with them? thanks.