Will a 1973 engine wire harness work on a 1978 or what years will interchange with each other thanks.

 

The engine harness will be different between those two years primarily in the distributor/coil wiring. The 78 will likely have an HEI distributor which requires a +12V ignition switched source for the distributor while the points style distributor the 73 came with stock will only have +12V for cranking then it will drop to ~6V to the coil.

As far as what other years will interchange, you can typically go up/down a few years. 75 was the first year that all vehicles were HEI distributor so I'd say 75 to probably 80 should be safe.

Whats wrong with your harness?

 

thanks swartlkk

The wires got caught it the steering shaft and pulled them out of the little black box that plugs into the fire wall.