Questions for the 300 inline 6 guys re: cable lengths

Hello Folks,

I'm putting together an order list for LMC, and I'm planning to order pos and negative cables for my 1980 project, along with a new starter cable.

For the negative cable, I'm going to do the same thing I did with my '84 F150 w/302. One negative cable from the battery to the bolt on the frame, and then another cable from that bolt to the block. Can anybody tell me the approximate length the cable would need to be from that bolt on the frame to the block on the 300 inline 6? (I also need to know where it attaches to the 300 block).

I also need to know the length of the starter cable for the 300/6. I'll be using the regular old starter solenoid/relay in the stock location on the fender, but I will be using a PMGR starter (if it makes a difference). Can anybody give me an approximate length for this one?

On my 1980, the negative cable goes from the frame to one of the starter mounting bolts.  I don't know the length offhand, but I'll measure my cables for you tomorrow if nobody responds before then with a definitive answer.

Cory, I do not have the length measurements, but I did something different. I ran a 2 gauge cable from the negative post to one starter motor mounting bolt and then ran another 2 gauge cable from the 2nd starter motor mounting bolt to the bolt on the chassis midway between the battery and the starter motor.

Oh, that's not a bad idea either David. Thanks for the tip!

By the way, 2 gauge is definitely overkill!

Cory, both the neg and starter cable connecting points are about 38" apart(sorry I didn't actually measure my cables). So depending on how you want to run the cables I'd go with the 48 and 49(43 and 40 could work to if you were going as short as possible and not connecting to the frame), just to be safe. Not sure about your plans, but with the EFI manifolds I have, the original route for the starter cable didn't work, so it's better to have extra to compensate for issues like that. And 10" is fine for the pos.

OK, I just got out from under the truck.  The lengths I measured are 24" for the negative cable from the frame to the starter, and 44" for the positive cable from the solenoid on the fender to the starter.  Hope this helps!

Thanks guys! Much appreciated for the info. That gives me enough info to place my order and a little extra length won't hurt and I can always adjust if necessary.

Dorsai wrote

On my 1980, the negative cable goes from the frame to one of the starter mounting bolts.  I don't know the length offhand, but I'll measure my cables for you tomorrow if nobody responds before then with a definitive answer.

Little late
Yep the way the factory did it.
New & old ground cables. I moved the frame tab over to the new cable.

The cable close to the exh pipe is the ground at the frame. The other cable is the pos. to the starter and it holds the cable from hitting the exh. pipe.

Both cables to the starter, you can see there is another "holder" to keep the ground cable from hitting the exk. pipe.


I used 2 gauge cables
Pos  battery cable to sol. I got 10"
Sol.to starter Ford cable I got 45.5" the cable I got was 48"

Ground from battery to frame to starter bolt Ford was 64" I got 55" or 4'.7" but that does not look right

I also have in my notes 8 gauge wire 20" long from the motor to fire wall on the left side of motor but think I went with a 10 gauge wire.

This may help others with a 300 six and the battery cables.
Dave ----

I'll be even later to the party, but for the sake of documentation:

On my 1984 300: (Going off memory and what was stocked at the time I bought such this Spring).

For the negative cable, I just used one of these from Walmart:https://www.walmart.com/ip/Everstart-LF51-4L-77-4-Gauge-Top-Post-Battery-Cable-51-Inches/16006693

(51 Inch 4 gauge top-post cable w/aux lead).

Fit perfectly. Routed it along the side of the engine bay down to the starter (which has a cutout in one of the flanges perfectly sized to fit such a cable)

I didn't bother with replacing the starter power cable, as somebody before me had already replaced it in recent times. I think it was probably one of these:

https://www.walmart.com/ip/Everstart-SS51-2-77-4-Gauge-Switch-to-Starter-Battery-Cable-51-Inches/16006698

(51 Inch 4 gauge starter cable).

The cable quality is surprisingly good despite being walmart parts... and at such a low cost, to me, it was the way to go. I wasn't going for an uber-stock build anyway (it's a farking battery cable, geez), so that's the route I went.