Yeah, I've used Plastidip as well heat shrink tubing on wire clamps but not hose clamps. The heat shrink tubing is more durable. I used it to cover the harness clamps attached to the firewall on FJ40.
I had a 3b headgasket leak in that same spot before but only under heavy loads and boost. I ran it that way for many years and miles. Are your head bolts 6 or 12 point? I believe that is the designation between TTY and the earlier design.