Remember the TBI is a constant flow return system to the tank so the lines will stay relatively cool when the fuel pump is running.
Also be sure to use rosin core solder for any splices and double wall heat shrink, the stuff that has glue in it so it seals to the wire insulation. I usually us a double layer for under hood splices, small heat shrink just big enough to slip over the solder joint about 1" long - shrink it then slip a bigger diameter heat shrink over the smaller one once its cool. Make the bigger diam. shrink about 3" long this provides excellent support and sealling for the splice.
51 GMC 4.2 turbo Can't solved today's problems using the same technology/thinking that created them
