Help Identify Burned Wire

[bigben5054]

What is this burned thing?

[bd]

The singed piece is the urethane insulator encasing the splice between the fusible link and the B+ feed to the cab.  The tubular heat shield is supposed to route from the starter solenoid directly rearward between the block and the exhaust header, directing the 12-volt harness up the back of the block away from exhaust heat.  With headers, a solenoid heat shield is also a good idea.

[bigben5054]

As always, thanks for your help.  Do I need to replace that insulator, or is it okay?

[bd]

As long as it appears cosmetic and isn't burned to the point of disintegrating or exposing bare wire or baring the splice, it will probably last indefinitely.  An example of a decent starter heat shield is imaged below along with the proper positioning of the wiring harness conduit that routes the harness behind the exhaust tubing next to the block, away from exhaust heat and razor-sharp edges at the rear corner of the block.

[bigben5054]

Thanks!