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Custom wiring harness suggestions?


Well-known member
Jul 3, 2001
Auburndale, Florida
1969 Killer Shark
I will be installing a more modern wire harness in the car. I have not found one specific to the C3. However, I have installed painless harnesses before and been very happy with them. It appears I may be making some small mods to the now finished firewall to retrofit the larger fuse panel. I am down to chosing between two options.

One, there is the universal painless 18 circuit that I have installed before in other cars. It is very nice and every wire labled. The down side, it does not have a bulkhead connector to the engine bay. It is around $300


The other option is the Painless Muscle Car harness. It has all the same stuff, plus it has an actual OEM style bulkhead connector to the engine bay and interior. It cost around $400.

Either way, I need to get this put together fast, as I intend to wire the car and install the computer and fuel injection harness before the motor.

Any thoughts?

Thanks for the suggestion. I will give them a call on Monday and compare apples to apples with the painless harness.

The one nice thing about the fuel injection, is the matched harness comes with the unit and computer straight from Edelbrock. So, at least I don't have to go hunt that down. I noticed that one you showed me here has some specific circuits for Fuel injection. Also, they appear to have more circuits than Painless, but it may also be the way they count them.

I will let you guys know. There was just no way I could even think about putting the stock harness back in. The previous owner had plugged the fuse box full of aluminum foil and the main connector was crushed. A total lost cause. Plus, I think I can still save the fiber optics.
Fiber Optics...

69MyWay said:
The previous owner had plugged the fuse box full of aluminum foil and the main connector was crushed. A total lost cause. Plus, I think I can still save the fiber optics.

Sorry Chris for the burst of laughter, but since you've gone through a complete ground up on this project, Why on earth would you want to save the original fiber optics???

Well, the fiber optics is just one of those little gimicks that makes the old Sharks cool. It really serves no real purpose at all, just coolness :grinshot
When you call Centech ask for Jim Stafford. He seemed to be knowledgeable.. :cool

Chris have you bouight the edlebrock system yet?
Have you looked at the system from Electromotive? Holley?
I would be interested in your decision making here. Although I'm sticking with a carb for now I may convert in the future. Thanks.

Regarding the wiring I am surprised an OEM harness can't be found but it is probably better to upgrade anyway. If you are planning electric fans and /or fog/driving lights you may want to engineer this into the harness as well. I am converting to H4 Euro headlights with dual high beams and low beams with a 55/100 wattage rating (total cost $180) and will have to upgrade the lighting circuit. OEM C-3 lighting is abysmal.
I would love to rewire mine as well, I hate the fuse block location and capacity.
Overall I would spend whatever you need to to get a real heavy duty system. You are unlikely to want to do this again :)
The Edelbrock system was a result of much research and personal experience with a variety of FI systems. I hate guess work, and don't have much interest in crate engines. Not that I don't believe in them, just that I have a fascination for doing all the internals myself. In fact, as you know putting an engine together from scratch is often no less expensive than a crate. Chevy has done an awesome job on the 502, 510 hsp fuel injected crate engine. However, the computer adjustments are permanent, and 510 is weak considering what else can be done with just a 454 .060 over.

Okay, with that said, I feel like for street use Edelbrock has done some of the most extensive research and development in the area of matched components. I have their heads on a small block that performed like a dream. I also know, matched components makes life easier if you have problems. Their FI (PRO FLO) system is one of the most user friendly on the market. Adjustments can be made without a laptop and calibrations are premapped. They have a system like you prefer where you can monitor the exhaust gas and make adjusments.

I settled on the full big block performance (539 hsp) package from Edelbrock. In extensive talking with reps from Holley, Edelbrock, and a variety of others, Edelbrock has been the most helpful. They have been there, done it. Again, these are street applications and may not appeal to the most hard core racer. The Pro Flo is good for an honest 10-15% more power over the above test mule that rated 539 hsp. If I have problems, I know that Edelbrock has the support network I need to get back on track. In fact, they helped me design the fuel lines that are already in the car for the future application of the Pro Flo unit.

No, I have not ordered it yet but intend to do so within the next two weeks (just now paid the credit card back down-system is about $2,400). The thinking there is to have it in conjuction with the complete wire harness to tie it all in together. Plus, I can find a suitable place for the computer now. It is a full multi port system with the main throttle body in the exact same location as you would find a carb. Therefore, mounting up the L88 hood scoop won't be a problem.

As far as Painless goes, they have several other items that extend wiring options. If I use them, I will get the additional power blocks and relay stations. This will allow me to have neat clean power for all the onboard equipment. I plan on using the space to the extreme left of the column under the hood area up against the plenum to mount the relay and junction boxes. I can kick up the headlight voltage through a high quality relay there.

The Euro headlights are an excellent choice. Better quality circuits will really help keep them bright and safe.

Right now, I am thinking about mounting the fuse panel on the inside of the air plenum where I sealed off the old Astro Vent. This gives me a little more room. The replacement panels are slightly larger than a stock panel.
That is a great write up... thanks
Thanks Roy,

I talked to Centech this morning, they are very helpful. He is sending me a catalog and we can discuss options further at that point.


You're welcome.. Hope it works out for ya...Thanks for the update..

I went ahead and ordered the Pro Flo fuel injection system along with the Oval port aluminum heads, Performer RPM Cam, Speed pro pistons, etc. etc. etc. today. I broke my $2,500 at a time debt on the old credit card, but what the heck.

The parts should be here in a week or so. If all goes well, I will paint the car in the next couple of weeks, and have the block ready to go to the machine shop.

I should get all the wiring harness stuff together soon, so I can tie it into the Fuel Injection system.
If you are looking for wiring harness or harness components for 53-82 Corvettes, the best place to go is Lectric Limited.

They sell reproduction harnesses that are specific to Corvettes.

The run by a Corvette enthusiast.

Ph: 708 563 0400
web: www.lectriclimited.com

Those guys have everything. I will have to check and see if they only do OEM style stuff. In other words, I am after the modern style fuses and some extra circuits never available in 69.

I will let you guys know what I find out.

Thanks again.
ccflorida said:
Any decision on the wiring harness??


Thanks for following up. The fuel injection was on back order and should be here this week. I went ahead and bought a Painless main harness and a seven circuit additional panel as Summit was able to put it together on a main order, free shipping, and discount. I will have to merge the Edelbrock computer harness into the Painless.

I got the full catalog from Centech and enjoyed speaking with them. Apples to apples, there is not much difference on the basic harness. However, Centech will custom build per the application. However, I don't need anything custom built for me as I am capable of reattaching the stock ends to the new harness myself and save big $$$$. So, there was not anything additional they could do for my situation.

I have roughed out the electric headlight actuators and am considering having Centech put together a one piece harness. Painless won't do that on a case by case basis. So, thanks to you I may still be doing business with them anyway.

:cool Thanks for the update. Glad to hear Summit gave you a discount and free shipping. Nice people to deal with..:beer

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