Do the engine wiring harness leads (with the fusible links) going to the starter have a conduit over them to protect from heat of contact with the back of the engine?
You can get grey stripe split loom tubing from wiringproducts.com listed under Hi Temp Nylon Loom. The grey stripe has a slightly higher temp rating of 300 deg. vs 275 deg. for blue stripe, but blue stripe has a fire retardant for short circuits $8.75 for a 10' length of 3/8". They have 1/4" through 1" 10' lengths and 100' rolls. Sam