Dont know, but i can check. Maybe 10yrs old longacer switch. What should all the measures be to get a passing grade?

I've checked them with an ohm meter and caught bad ones. But it's a big difference when trying to run a few hundred amps through it. I usually just change them out occasionally or if an issue pops up. I would think a voltage drop test from the battery positive to the output stud of the main switch, while the starter is engaged, would show any issue with the switch.

Another reason I don't run my starter cable through the cut off. It's death by a thousand cuts killing them regardless of momentary rating. Sometimes they will weld themselves in the on position and the switch won't work at all.

A test that only requires a wrench, hook the battery up to the downstream/starter side of the cut off and test it. Turn the key. If it does the same action as when going through the switch, you can scratch it off the list.

Ok, ill check that.

Dave take a few mins to go to youtube and look up "voltage drop test". once you understand how to test, your electrical problems will go away and any that come up can be solved quickly. this is a skillset that every DIY'er should know how to use.

also the correct answer is "0" voltage loss across the switch.

climbing down off of soap box

Joe

Ok. Thanks for that.

Correct, any resistance across a switch, replace it.

Was looking at a Ron Francis catalog this morning for something and ran across his trunk mount battery cable kit for street rods with EFI, power accessories, etc. 1ga.

I would , and do , use either #1 or #0 for my trunk mounted batteries depending on the compression and if it is a street car or race only car.
#0 on race only cars with multiple grounds also

I just picked up my wire, 1/0 to the starter and #4 for the charge wire and to the feed up front. Also my starter wire will not go through my disconnect switch.

Most tech guys track test is to flip the switch to off and have you try and crank. Better make sure it shuts the starter solinoid feed circuit off if the starter main feed doesn't go through the switch.
Doug

It will.

Rule book says master switch must shut off all electrical functions. Ever have a starter "stick", solenoid jam and keep the starter engaged? I have. How you going to fix that when the starter is hooked directly to the battery? If running the starter smokes your master switch, you need a better master switch.

My Longacre master switch is getting very old at this point. Still shuts everything off.

I used aircraft wire, it has like 120 strands in it in a 1/0 size, and it can handle the amperage of a standard wire that is 1 size larger. Tim