MALIBU V6 to V8 Engine wiring harness help

Buford T. JuSStice

Buford T. JuSStice

Master Mechanic
Aug 16, 2010
280
111
43
#1
I swapped out the 3.8L 231ci V6 in my Buick Century (I labeled it as a Malibu because Century isn't available) with a 6.3L 383ci V8 SBC. The wiring that was originally in the car SEEMS to be long enough to do what I need it to do but is it thick enough? There is a cable that seems to go to the starter that is two wires joined into one at the end on an eyelet, and is tee'd off at one point... that one I assume goes to the starter at the eyelet, and the tee off goes to the Passenger side of the vehicle. The tee-off has a connector that is melted, which is no big deal, I can always install a new connector and put a heat wrap around the whole thing if need be.

There is a small cable that is about as long as the large double wire set up I mentioned, and it seems to be the trigger wire for the starter.

The wire that goes to the alternator is pretty obvious, and is about twice as long as I need it to be thankfully, however the kit I got for the SBC has the one wire going to the firewall, and four wires coming off of it instead of just one. Are those hot on ignition so I can use them for sensors?

The ignition wire is also much greater in length than it needs to be since well... it's pretty much right there on the firewall, whereas on the Buick V6 it's way up front.

Other than that I don't think I even need any other wires. The wiper motor has it's own little harness and it isn't changing, the horns, headlamps and all that aren't changing either.

Only thing I really need are GOOD battery cables. Any recommendations that are still readily available? Original Parts Group has a set but they're on back order for at least a month.
 
pontiacgp

pontiacgp

Canadian Prime Minister
Mar 31, 2006
23,752
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Kitchener, Ontario
#2
the wire gauge for the v8 and v6 cars were no different, like you noticed it is the length of the wires is the issue. If you have a recycling yard close you could see if you can find a wiring harness for a v8. The wiring harness for the headlights won't need to be changed. There is a 7 mm bolt in the middle of the two harnesses on the back of the fuse box.
 
timo22

timo22

Master Mechanic
Supporting Member
Sep 10, 2012
437
495
93
St. Louis,Mo
#3
I'm about to wire up my Bonneville. Had the 3.8 and put a SBC in it. I know exactly what you are talking about. I tried to find a V8 harness but had no luck. I plan on fitting the harness and cutting the wires to fit. Then solder and heat shrink.
timo22
 
Buford T. JuSStice

Buford T. JuSStice

Master Mechanic
Aug 16, 2010
280
111
43
#4
Well I mean, that's the thing... it doesn't seem like it's too short at all. It's long enough to go from the fuse block all the way over the passenger fender and then drape over at least six inches. My biggest issue is making sure I don't put it in a place where it'll get melted by the headers I've got for it.
 
pontiacgp

pontiacgp

Canadian Prime Minister
Mar 31, 2006
23,752
4,366
113
Kitchener, Ontario
#5
With headers I use a Ford style remote solenoid so the only wire going to the starter is the battery cable which is only live when I start the car.
 
Buford T. JuSStice

Buford T. JuSStice

Master Mechanic
Aug 16, 2010
280
111
43
#6
I might just use the stock wire and put them in a heat shield sleeve kind of like how I plan on doing with the spark plug wires.

As for those extra wires coming off of the alternator... those are hot when the ignition is on, right? I wonder how much current they're meant to carry. If it's 5V then they'll be good for signal wires, but if they're 12V then maybe they'll be good for something else.
 

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