Mounting battery in the trunk questions, electrical questions...

[Strawdawg]

I was just wondering if 400 amps would be enough, or if in some conditions, starting might trip the breakers....as I said above, there are a lot of variables.  I would like to think that is large enough, but, ??

I have seen some starters that pulled more than that for an instant...

Google offers a variety of opinions from no way to works for me on the circuit breakers

Our starters normally don't seem to pull as much amperage because they are gear reduction instead of direct drive so it takes less current to turn them over.

An alternative, which I think has been mentioned, would be to put a solenoid in the truck and trigger it with the normal yellow wire from the ignition switch.  That way the battery cable would not be hot except when starting.  Then run a 6 ga wire to the battery from the alternator using a fusible link, maxi fuse, or circuit breaker on it in case it got shorted.  Might be easy to run it thru the interior so that the likely hood of it getting cut were close to zero.

[brads70]

The new Chargers and Challengers have the battery in the trunk. Are they fused along the cable that goes up front?

[dodj]

How much current does the starter pull when cranking?

I would guess, 200-300 amps initially. could be higher. You get away with cable that rated for less current (#4 etc) because it is for such short duration and infrequent use.
Personally, i like the solenoid isolation idea rather than a breaker. Current spikes incredibly high at the first moment of trying to crank the engine and may wreak havoc with breakers 

[HP_Cuda]

Most likely somewhere around 200 amps I would guess but if you have an ammeter like this:
http://www.sears.com/craftsman-digital-clamp-on-ammeter/p-03482369000P

I have the older version of this but it has the same capabilities, heck I've put it on my house mains to see when everything is running what kind of draw we were having. Based on using 0 or 1 guage below that would keep you within the 200 amp specs but it can handle short spikes before melting down. Cool thing about this wire chart is that for each given wire used it will tell you the Ohms or resistance for each.

Amp ratings per guage wire:
http://www.powerstream.com/Wire_Size.htm

The solenoid in the trunk is not a bad idea which can be controlled from a switch and ignition or both. Kinda like the NHRA regulation to kill the motor from the back of the car (master cutoff) which is not a bad idea.

[brads70]

Ok another question...
I seem to have quite a few things that need ign/key on power. How do l safely wire in a junction or distribution block. Where exactly do I connect to the stock harness?  Or would relays be the way to go?

[dodj]

I guess first you would have to decide where you would like to put it. As for relays, it would depend on what you are connecting. A high current demand device like a blower motor or headlight? Or something small like a solenoid?
The relay deal is mainly to get the high current draw items off the bulkhead connector and out of the interior of the car.

Actually, just looking at my '73 service manual. When the dealer upgraded you from 37amp to a whopping 60amp alt, they cut and taped the bulkhead connections and ran separate power wires through the firewall into the dash amp gauge.

[brads70]

I guess first you would have to decide where you would like to put it. As for relays, it would depend on what you are connecting. A high current demand device like a blower motor or headlight? Or something small like a solenoid?
The relay deal is mainly to get the high current draw items off the bulkhead connector and out of the interior of the car.

Actually, just looking at my '73 service manual. When the dealer upgraded you from 37amp to a whopping 60amp alt, they cut and taped the bulkhead connections and ran separate power wires through the firewall into the dash amp gauge.

I assume ign power will be taken somewhere under the dash, so I guess I'd mount it under there too.

[Strawdawg]

Brad, the wiring in my car was pretty much wasted from age, rats, and fire from the ammeter.

After patching it up, I decided to build my own dash cluster so I hacked most of it out and wired it more like a street rod.  I used some of the old GM junction boxes for power points   http://www.ebay.com/itm/64-65-66-67-68-69-70-71-Camaro-Firebird-Chevelle-Nova-Battery-junction-block-/330897901793?pt=Vintage_Car_Truck_Parts_Accessories&hash=item4d0b0d48e1&vxp=mtr

In my case, I bought a hot wire in from the battery, bypassing the charred bulkhead connector and connected it to this under the dash...mounted it on the end of the heater box.   Then I connected my ignition feed to it.

I put another one under the hood on the firewall and ran the blue and brown wire from the key to it (I am not using a ballast resistor so I could hook them together under the dash.  Then all my ignition power devices connect to that point under the hood.

I used 8 ga wire so I don't have to worry about overloading the feed.

these blocks are not very big and I have used them on the Challenger, my Buicks, and my jeep.  Oh, yeah, I use them on my Camaro as well.

[HP_Cuda]

This. will work.

Junction blocks will allow you to go in a bunch of different directions instead of going directly to your harness.

I guess you could do the same with relays but it's entirely up to you how you want to pull it off.

B

[brads70]

In my case, I bought a hot wire in from the battery, bypassing the charred bulkhead connector and connected it to this under the dash...mounted it on the end of the heater box.   Then I connected my ignition feed to it.

I put another one under the hood on the firewall and ran the blue and brown wire from the key to it (I am not using a ballast resistor so I could hook them together under the dash.  Then all my ignition power devices connect to that point under the hood.

I used 8 ga wire so I don't have to worry about overloading the feed.

Bare with me.... electrical I'm slow with... 
So if I understand this correctly you used the GM studs to make another 12v battery connection point under the dash and another GM stud under the hood for 12v key powered using the ballast resistor wires (brown and blue) to feed it?
I don't use the BR either (MSD box) , what I'm trying to figure out is what I tap into with the stock wiring to get 12v ignition power. In your case you used the old ballast resistor wires, correct?

[Strawdawg]

I cut off the blue and brown wires at the connector under the dash at the column,  soldered them to an 8ga wire. . Put a grommet in the firewall and ran it thru to the block under the hood.  Did the same thing bringing power in from the starter relay/battery to the red wire going up the column.  Connected it to a block under the dash and the red wire from the column to it

[MTS-Challenger]

One wire alternator?
I wonder how much voltage drop your getting by using an alternator without remote voltage sensing?
 

[brads70]

I cut off the blue and brown wires at the connector under the dash at the column,  soldered them to an 8ga wire. . Put a grommet in the firewall and ran it thru to the block under the hood.  Did the same thing bringing power in from the starter relay/battery to the red wire going up the column.  Connected it to a block under the dash and the red wire from the column to it

I got it now! Thanks that clears things up!

[brads70]

One wire alternator?
I wonder how much voltage drop your getting by using an alternator without remote voltage sensing?
 

Don't know yet alternator is being shipped.

[dodj]

I assume ign power will be taken somewhere under the dash, so I guess I'd mount it under there too.

You can install a distribution point under the dash or in the engine compartment. If the equipment you are going to power up from it is in the interior/trunk, that's where you should put it. If it is for fans, lights, pumps etc it should be in the engine compartment. That way you only have one large wire going through the firewall instead of several smaller wires. 
Or...do both.