You just need to do a good visual inspection of the existing harness and then, chances are, some wires may not be long enough to reach to different spots like possibly the oil sender wire, the water temperature sender wire, the starter solenoid and so on while some may also be too long and that's fine.Hi All,
We are replacing the original 250 in a 76 concours with a 350. Need to know if I need to replace the wiring harness as well ? The previous owner had some rewiring done and the harness looks great, hate to replace it if I don't have to.
There will be differences in the wiring harness depending on factory installed options but they go in a matched set. In other words if the car was originally equipped with optional gauges then under the hood there would be wires for the tachometer and then the interior/underdash harness would also be different to support the optional gauges. You cannot expect an engine harness designed for no gauges to work with an interior underdash harness setup for gauges. In your case you are just swapping motors and both will need to be setup with the proper sensors. The indash oil light could care less if the oil sender was on a 4 cylinder, a 6 cylinder, or a big or small block V8. The same for the water temp sender. The crank wire for the starter solenoid does not know if it's connected to a 6 cylinder starter solenoid or a V8 one.thanks jim,
i'm completely comfortable doing any mods (shortening or lengthening) and am OCD about making the wires match. i just wasn't sure if there was any differences in under the dash or engine compartment connections.
This is my sons car and he is paying for everything, and just 16 and not working yet, so glad he won't have to drop a couple hundred on a wiring harness. has too many other parts to spend money on.
As far as the wiring goes, changing from the standard warning light cluster to one of the factory optional gauge clusters isn't all that difficult. It's basically a matter of re-pinning the cluster connector, changing out the temp sending unit, and making a few changes to the alternator wiring to deal with the lack of a "gen" light in the gauge cluster.Which leads to another question - there's a 78 rally cluster for sale in the classifieds and i was wondering if it would work on his car? Based on what you said i am guessing the answer is yes, if i change out the harness, which i would have to do anyway if i wanted to upgrade.
You're welcome. The 75 & 76 Nova dashes actually share more in common with the 69 - 74 dashes than they do with 77 - 79. So that might be another alternative to look into depending on what you need for parts and/or the style you want to go with. There were some styling changes, but for the most part, the 69-74 dash pads, instrument clusters, and bezels will be a direct fit into a 75 or 76 and have the ability to mix & match with existing 75/76 parts (unlike 77-79 where you would have to change everything over to that style so the pad/bezel/cluster all fit together).wow, thanks ray. that's a lot to think about. i can't seem to find any replacement dash parts for his 76 so if it would fit we may just upgrade the entire dash to 77-8 parts.
Interesting! Yes, it does indeed sound like his car already has the 77-79 style dash. In which case that 78 gauge cluster you found should be a direct physical fit with just some wiring changes to make it functional. However, with that style of cluster/bezel, you'll have to stick with the 77-79 style dash pad ... the earlier year pads won't come close to fitting up correctly against the bezel.i am starting to think maybe he already has a 77 dash???