The long engine mount I have is identified on the invoice as EM-07  320/360 Dyna-1 (long). It replaced EM-04, the standard length engine mount used with a short' horizontal stabilizer. It has never been mounted on a firewall.  It was used by Lancair in the mid 2000's to create a jig for someone building mounts for Lancair, I was told.  Lancair returned it with a new white powder coat.  I also have 4 never used, in original boxes , rubber vibration isolators, identified on the invoice as "94150-41, isolator, vibration (290/320/360)  Dynafocal for 290/320/360 constant speed or fixed pitch.  I will sell.  I'll call Lancair to get an idea of what its value is.  I am open to suggestions as to how to determine its value.