12v Ignition source in 67

[TwinsSpeedShop]

I used the factory ignition source in my 67 when I did my hei swap and it worked fine. Now that I'm doing my LS swap, that wire doesn't seem to keep a full 12v during startup. What is everyone using for their ignition source for power the fuse block and computer. The factory wire is a resistance wire if I'm correct, can I just cut the wire close to the firewall bulkhead and run new wire from there or do I need to go to the switch and run a wire out ?
Thanks in advance

[truckdude239]

umm i used my hei wire for it but i had installed an classic update kit from american auto wire installed that the hei was 12 volts

[TwinsSpeedShop]

thanks, truckdude, I'll just have to go to the ingnition switch and run a wire out for it. The resistance wire that come out of the bulkhead is dropping voltage

[dec010974]

I used the factory ignition source in my 67 when I did my hei swap and it worked fine. Now that I'm doing my LS swap, that wire doesn't seem to keep a full 12v during startup.
Response
Have you tested that source with a test light while cranking? Also, Are you referring to the wire with the white cloth coming from the bulk head? If my memory serves me correctly, I ran that wire to a fused block like the attached pic, (2) of them, fused and used this for my ignition sources for my LSx swap. I hope this helps. I'm no electrical engineer, but worked for me. Pm me your number and I'll text you a pic. I added relays to this fuse block to keep my electrical items in check. Since then, I have also rewired the 1971 c10. 40+ yo wiring gave me the shakes. I keep reading on this forum about fires with old brittle wires. It was sign to replace the wiring. Good luck twinsspeedshop.

[dec010974]

Here's the pic. I put (2) of these together. But the one I used has a copper bar with four of these pins connected.

[TwinsSpeedShop]

Originally Posted by dec010974

I used the factory ignition source in my 67 when I did my hei swap and it worked fine. Now that I'm doing my LS swap, that wire doesn't seem to keep a full 12v during startup.
Response
Have you tested that source with a test light while cranking? Also, Are you referring to the wire with the white cloth coming from the bulk head? If my memory serves me correctly, I ran that wire to a fused block like the attached pic, (2) of them, fused and used this for my ignition sources for my LSx swap. I hope this helps. I'm no electrical engineer, but worked for me. Pm me your number and I'll text you a pic. I added relays to this fuse block to keep my electrical items in check. Since then, I have also rewired the 1971 c10. 40+ yo wiring gave me the shakes. I keep reading on this forum about fires with old brittle wires. It was sign to replace the wiring. Good luck twinsspeedshop.

That would work as that wire adds resistance the longer it is. I'm still going to find one at the switch and go from there. Thanks for the response

[JMac11]

I was thinking of pulling the wire out of the harness, replacing it with a new Male P56 Plug and 10 Guage wire to the Key On Part on the Harness..... I know that works on the Hei Swap.

[Gobuffalo]

Follow the cloth covered resistor wire to the plug on the fire wall where it goes into the fuse box. Remove the plug (remove the bolt between the 2 plugs). Compress the locking tab on the resistor wire and pull it out of the plug. It's a copper spade connector. You can buy these at a real auto parts. Replace the cloth wire with no. 10 or bigger wire and your new spade connector an put the plug back together. Hide it back in the loom, make it long enough to hook up.
I like pink because it's the same color as the ignition switch wire. All your after is gritting rid of the old resister wire.
Done this on a few trucks for me and others, never had a problem. You are still using the same circuit so tracing a future problem is easy.

[TwinsSpeedShop]

Originally Posted by Gobuffalo

Follow the cloth covered resistor wire to the plug on the fire wall where it goes into the fuse box. Remove the plug (remove the bolt between the 2 plugs). Compress the locking tab on the resistor wire and pull it out of the plug. It's a copper spade connector. You can buy these at a real auto parts. Replace the cloth wire with no. 10 or bigger wire and your new spade connector an put the plug back together. Hide it back in the loom, make it long enough to hook up.
I like pink because it's the same color as the ignition switch wire. All your after is gritting rid of the old resister wire.
Done this on a few trucks for me and others, never had a problem. You are still using the same circuit so tracing a future problem is easy.

Thanks. You will have to excuse me this time as I haven't looked yet, but does the cloth resistance wire go all the way to the ignition switch or just from the fuse block out?

[Gobuffalo]

No it ends at the fuse box.