willie Posted March 21, 2021 Share Posted March 21, 2021 I am wondering if a engine wire harness for a 71/350/350 is the same as an engine harness for a 71ss 454/400? This 71ss that i am staring has many loose wires that have no ends and the ends that it does have look to be melted, broken, or damaged. I do have a 71/350 parts car that the harness looks to be in good shape. Rather than cut off ends and reinstall them on the ss i just thought i might be able to pull both harnesses and install the good one back in ss. Also is the coil and mounting bracket the same for them also? What do you guys think? Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted March 21, 2021 Share Posted March 21, 2021 Hey Willie. The 350 harness should work. I have converted small block cars to big blocks and used the small block harness. Only thing is if it's a gauge car or an idiot light car. The engine harness must match whichever the dash is. Quote Link to comment Share on other sites More sharing options...
Mike Brichta Posted March 22, 2021 Share Posted March 22, 2021 Hey Willie, There are a couple of things to consider with harnesses: - if the years are the same it is much easier to interchange harnesses - gauges vs idiot lights - AC cars vs non-AC harnesses If you have the 71 harness for a 71 car, half the battle is won. Good luck!! Mike Quote Link to comment Share on other sites More sharing options...
Paul Bell Posted March 22, 2021 Share Posted March 22, 2021 I think there's a difference between small block and big block engine harnesses-but I can't remember what it is just now. That makes two for small block and two for big block. The AC harness is an add-on separate harness not connected to anything in the engine of forward lighting harness. Quote Link to comment Share on other sites More sharing options...
willie Posted March 23, 2021 Author Share Posted March 23, 2021 Thanks guys, Upon further inspection of the 350 car there are also some cracks and damage. Not nearly as much as the SS though. So i might as well just buy an engine harness for her. I repaired some on the light harness already. So i would only need the one harness. It doesn't look like the colors are correct any way on the 2 different harnesses. I do have some questions though, There are 2 green 1 with a white stripe on the left side of the motor, where do they go? ( on the 72 custom there was one on each side of the motor, both for the temp gauge. Not sure for the 71SS"s. They are NOT the a/c wires because i have them and put them to the side. Also on the left side there are 2 wires together 1 orange and 1 black, where do they go? There are other wires but haven't cleaned them enough to know the colors, but they are very thick wires. And all 3 sets of these wires have no ends. Thx for the help guys Quote Link to comment Share on other sites More sharing options...
1Bad454 Posted March 23, 2021 Share Posted March 23, 2021 These guys make factory reproductions if you're not aware. http://www.wiringharness.com/ Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted March 23, 2021 Share Posted March 23, 2021 Have the M&H engine and front lamp harness in my 70 SS. Fit great and correct connectors. Quote Link to comment Share on other sites More sharing options...
rotinrob Posted March 24, 2021 Share Posted March 24, 2021 For the cost and piece of mind they provide buy a new harness, unless of course you have a survivor type car. Plus you can get an HEI/non resistor wire harness. Some places might also remove the TCS wiring if you would like to not have those wires hanging around. I have used many different suppliers on projects in the past and all the usual suspects provide decent stuff but don't toss the original harness as I have found some connecters are different color than the original. Changed all the harnesses on my 70 SS except the under dash with minimal disassembly required. Also needed to do some modification to the distributor feed (HEI type harness) to work with the mini starter. The mini starter only had a start terminal so I hooked the other wire to the starter feed side of the solenoid (only hot when the starter is engaged) through a diode to prevent back feeding in run mode from the switched wire in the harness. This provides maximum voltage to the ignition while the engine is cranking just as the General had planed. Probably not needed unless running high compression big blocks. rotin Quote Link to comment Share on other sites More sharing options...
willie Posted March 25, 2021 Author Share Posted March 25, 2021 I will probably get another harness but the main problem with this one is, the thick purple wire that runs across the firewall was cut (goes to the starter) and just taped up. There was another thick wire coming thru the firewall from a purple with white stripe wire under the dash that he jumped off of. Does anyone here know why? Unless there was a short in the harness that he cut and taped the outside purple wire and spliced a jumper wire from the purple with white stripe on the inside under dash (for power to the starter)???? Quote Link to comment Share on other sites More sharing options...
jft69z Posted March 25, 2021 Share Posted March 25, 2021 Purple with white is neutral safety switch wiring typically if I remember correct. May have just bypassed the NSS or picked off of it directly, not sure. It will still make it's way to the starter, but the NSS is there as a safety interlock. Quote Link to comment Share on other sites More sharing options...
DaveC Posted March 27, 2021 Share Posted March 27, 2021 On 3/21/2021 at 7:30 PM, willie said: I am wondering if a engine wire harness for a 71/350/350 is the same as an engine harness for a 71ss 454/400? This 71ss that i am staring has many loose wires that have no ends and the ends that it does have look to be melted, broken, or damaged. I do have a 71/350 parts car that the harness looks to be in good shape. Rather than cut off ends and reinstall them on the ss i just thought i might be able to pull both harnesses and install the good one back in ss. Also is the coil and mounting bracket the same for them also? What do you guys think? Hey Willie, Don't do anything just yet!! I think I bought a second engine harness for my 71 SS when I meant to get my light harness....thinking I have a spare. Quote Link to comment Share on other sites More sharing options...
willie Posted March 27, 2021 Author Share Posted March 27, 2021 Ok Dave that sounds good!!! Let me know? Tkx Quote Link to comment Share on other sites More sharing options...
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