It is an easy DIY project, (couple of hours), if you don't care about appearance.

Just replace one wire at a time. The gray plug has small gray plates on either side that pop off and allow you to access the wires individually. If you slice through the loom/sheathing that the wires are in, you'll be able to trace and replace each one seperately.

The bullet plugs in the gray connector may be hard to find (dealer has them for 50 cents each?) so when you make the cut leave enough wire on the plugs so that you can attach replacement wire. I used blue crimp-on butt connectors, instead of pink, as they fit over the plug ends. I also sheathed the wires individually with teflon polytube (hard to find so could use vinyl tubing found in small diameters in hardware stores for fluids as they're heat and oil resistant). Reroute some wires (eg oil, alt) and bundle them together with zip ties.
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1980 245 Canadian B21A with SU carb and M46 trans