I have been thinking of how to seal the electrical loom passing through the firewall. I purchased a silcone hose reducer ( 1.75" to 1.50" ) which I have shortened and split. I don't know whether this will work, so I had a trial fit on the loom and clamped it on the firewall carry through bracket, which I had made some time ago for this exact purpose. I think this may be an option. I need another hose clamp which I will purchase in the next couple of days.