Instead of having several posts i wanted to ask a few questions in this one.

I am near the end of a 383 LT1 build with a new stand alone harness and all new autometer gauges. I have an electric water pump. The wiring harness has two fan relays and a fuel pump relay.

1. I have an MSD 6AL ignition box and there is a tach out put. My harness also has a tach wire. How should i wire up my autometer tach?

2. There are several +12v wires that need to be connected from the stand alone harness, c100, and MSD so i have a junction block where the battery cable comes into and all the wires needing a constant +12v are connected here as well. I was going to run another heavy ga cable to the starter from here. Is this ok? I mounted in the interior near the top of the firewall on the passenger side.

3. I did something similar for grounds. There are 3-4 grounds i have including the MSD on the interior for the wiring so i put them all into a junction block and then a heavy gauge wire to the top of the firewall. I ground off the paint and connected with the washers with the little teeth. Will this be ok for grounding? I was going to run an extra cable to another metal surface as a back-up.

4. How should i wire the water pump? It has one blue and one black. black i assume is ground but i'll check with mezzier. Blue should be power and i imagine this should hook up to something where i only get power when the motor is running or when ign is on. Any ideas where i can easily wire this in the engine bay instead of running a wire all the way into the passenger compartment to tie in with IGN wire?

5. I have the Aeromotive A1000 fuel pump and it came with all its own wiring and relays but my stand alone harness has a relay already. Can i just wire the fuel pump ++ wire from the harness to the A1000 and ground the A1000 and be done with it? Anyone ever do anything like this? Or should i wire up using Aeromotive relays and just hook the positive connection to the fuel pump ++ wire of the harness? It'll have two relays then, not sure if that will be a problem or not.

6. The ground wire for the MSD 6AL says to go to battery ground. Does it have to go to the same ground as the battery? or can it be a chassis ground in the passenger compartment? I have my battery relocated to the rear so it would be a long ground wire which i dont think is a good thing.

Have more but cant remember right now... lol. I appreciate the help everyone.

 

Pos battery cable should run directly to the starter. An additional large gauge wire from the battery pos or the starter can run to the power distribution block you have - but pos battery cable needs to go directly to starter.

Neg battery cable needs to go directly to the block. Then there should be a ground from battery neg to the fender/body, and another groundstrap from the block to the firewall/body.

This is necessary because the starter draws an excessive amount of power for starting, and as such needs the pos battery cable connected directly to starter. As well, this circuit needs a huge ground, and the starter grounds itself by being connected directly to the block, thus the need to have the neg battery cable connected directly to the block - the entire starter circuit (pos & neg) requires ALOT of amps, and thus the circuit needs huge wires, thus the big battery cables need to be used.

The water pump I would imagine would be best served by a relay - the relay gets 1) ground, 2) an "exciter" wire, 3) battery power, and 4) wire to the pump. #2 would be any hot-in-run wire (relay needs very little amps to excite the coil inside, so tap into any hot-in-run). #3 would be a wire from your pwer distribution block. #4 would be your blue wire from the pump. That way, the water pump can feed off of 12v+ directly from the battery (through the power distribution block), but only get fed when the relay is activated by your hot-in-run wire.

The MSD box can be ground to the body - just make sure you have a nice sized wire from battery neg to the body so that it can supply all the necessary grounding it has to do for the whole car.

I don't see why you can't use the relay that came with the harness for the fuel pump - then you can use that fuel pump relay for the water pump as I explained without buying another one.

 

Thanks. Does it matter that the ground cable is going to be LONG because the battery is in the rear tire well. I dont mind doing it but just asking.

I've always heard of people moving the battery but no one ever talks about running the power and ground cables... i guess because its just a common thing.

I appreciate the comments. I hope to get all the wiring done this weekend and the gauges in.

I still need to figure out the tach/MSD 6AL/and tach wire from harness issue.

 

I'm not 100% sure how battery relocations are done - I know the pos battery cable has to run all the way to the front, but neg I don't know - maybe they just ground neg cable to the body and then run a realy heavy ground to the block from the body - I just don't know.

 

You run a heavy ground cable to a really good ground point on frame at rear ( think big bolt / clean surface ) at rear then similar from frame to block at front
Saves having to run a heavy Neg wire all the way to front

 

I didnt look before but this is exactly what the battery relocation kit I have is setup for,

I am running long red from battery to starter and heavy ground at the battery to chassis. I'll grind the surface to bare metal just to be sure.

I'll have a chassis ground from the engine block to the frame and if i can i'll do it in two locations on the block or maybe from one of the heads to the frame.

I have a power junction block on the inside of the firewall where i will run the alternator to and then another power wire from here back to the battery. does that work ok? I saw a few diagrams online that showed this was ok.