Wiring harness suggestion

[tim's68gmc]

I am restoring a 1968 Gmc 3/4 ton camper special. I have replace the original cab with a 1970 Gmc cab, any suggestions on what year I should purchase a wiring package for or are they the same?

['68OrangeSunshine]

Hi I have a '68 Chevy C/10 Stepside and a '71 GMC Jimmy K/1500 [4x4].
I'm not sure what the wiring is like on the '70, so I'm only guessing here.
Chevy and GMCs differ in the number of headlights, but since both your cabs are the same make, there's no issue there. [Just be sure to specify GMC when you order.] The '68s do not have wiring to the Side Marker Lights -- they are reflectors only, but on the '71s they light up, and the front markers blink when the turn signal switch is selected. Rear markers do not blink turns but all flash in unison in Hazard mode.
I used an M&H Electric harness in my Jimmy. They are first class, hand-made in the USA, and the technician who assembles your harness puts his name on it. Factory-type connectors, perfect lengths, and correct color codes. M&H is not cheap, and there is a wait, but IMHO it's worth it.
If you specify HEI and/or Voltage Regulator-Deleted Alternator, they can build that into your harness too.
Also the Fuse Block in the cab will have a different orientation. One is vertical and the other sideways. But I'm not sure if the one will bolt into the other style. You have to decide if you want to be 1968 Period Correct and have reflectors-only or customize and upgrade to '71-'72 standard and run the wires and sockets to the Side Marker Lights. Might cost a little more, but it's safer to be seen at night and it would match your '72 Jimmy.

[csfields]

American Auto Wire. I put a complete kit in my truck, piece of cake.

[tim's68gmc]

thanks for the info

[leftybass209]

Is your wiring all chopped up underneath the dash? I'd suggest pulling the harness out (if you have one) and accessing the condition. In both cases my fuse panel and attached harness was in great condition. I only needed an engine harness. I'd recommend m&h wiring if your restoring. If you're resto - modding and want modern blade fuses that's a different beast.

[ujsf01]

Ditto to CS's post. I sell and install American Autowire and wouldn't use anything else. Plenty of length to route it hidden if you like, OE style connectors and colors. Plenty of expansion circuits. Not to mention, fantastic customer service. Ask for Josh and tell him I told you to call. My business name is Hot Rod Electric, LLC.

[BrianG]

One more vote for American Autowire... Go with the classic update series.

[HeavyD]

Does AAW require any firewall mods?

[Mr.Hyde]

I used a ezwiring kit 12 circuit, wish I would have gone 21 but overall it was the worst experience of my life still finishing a few things and testing them.

[csfields]

Originally Posted by HeavyD

Does AAW require any firewall mods?

Some slight trimming around the original bulk head harness goes through the firewall. It's slightly larger. Not sure if its because if the blade fuses or wire is heavier? Like I said it's just some trimming. They send you a template which make it easier as to how much has to be done. Other than that it's all the same.

[tim's68gmc]

Thanks all for the help this will get me going in the right direction.

[MoFormula]

Just starting the AAW Classic Update install on my 1972 GMC. Did have to enlarge firewall opening about 3/8" on two sides. Not a difficult task. Just started dash wiring. So far very clear instructions and not too bad. I am mechanically inclined but NOT a mechanic by any means.