Power wire for MSD and Vintage Air

[tonyvol]

Hey guys, does anyone know why MSD and Vintage Air wants you to hook their power wires directly to the battery? Vintage Air also wants the circuit breaker to be as close to the battery. I would like to have it hidden under the dash. I'm wiring my 67 Camaro and I'm using AAW Classic Update wiring harness. I put the battery in the trunk with a remote solenoid. The alternator wire passes through the firewall using a battery feed stud and I wanted to hook the MSD and Vintage Air power feed stud. I want to keep the wires hidden as much as possible under the dash and don't want to have a bunch of wires hanging off the battery. Does anyone know if this will work or if I need to have the power wires hooked directly to the battery

http://www.summitracing.com/parts/aww-500009

[sjaroslo]

I'm planning to do the same thing for my Vintage Air connection, connecting to the inside stud of the bulkhead pass through. I think I remember a thread on here that John Parsons responded to with a thoughtful explanation, but I'll be buggered if I can remember the points that he made.

[astroracer]

Most of the reasoning for hooking directly to the battery is to get clean power. You can hook the components up to a power distribution block if you feed that block with large enough wires to carry the total load. I always oversize wiring when building a harness from scratch. My Astro van has 4ga alternator wires and nothing under 8ga for the charging circuit. The alternator 4ga. output goes directly to a distribution block which then feeds the main harness and charges the battery in the back. Larger wires are especially necessary with the battery in the back. Those long runs can create some hot wires if they are to small to carry the load.
Mark

[tonyvol]

Hey guys, I ran a 4 ga. fine strand copper wire from the ALT to the battery in the trunk. I was thinking of putting a distribution block off of that wire where it hooks to the bulkhead pass through. I want to put the distribution block under the dash. I wondering if this will work to power the AC and MSD box? Thanks for the help.

Tony

[astroracer]

Yes, that will work fine. Just make sure the power wires are the correct size and everything is fused as recommended from the manufacturer.
This is what I did on the van. I picked up a 4th gen F-Body distribution block from my local GM dealer. It mounts just about anywhere with a few mods. If you mount it in the engine compartment it is much easier to access for adding components. The distribution block install starts in thread #629.
https://www.pro-touring.com/threads/20086-The-BAD-AST-Project-Faze-II/page32?highlight=astroracer

[tonyvol]

Thanks Mark and Steve for the help.

[juggernaut]

I have Vintage air, MSD Digital 6, and AAW classic update harness in my camaro. I'm powering my MSD box, mounted in the glove box, off the 6 wire accessory connector. The vintage air system is powered off the brown wire that would feed the "heater switch" aka the blower fan switch. I haven't had any problems to speak of. I can't see why a distribution block wouldn't work.

[tonyvol]

I have Vintage air, MSD Digital 6, and AAW classic update harness in my camaro. I'm powering my MSD box, mounted in the glove box, off the 6 wire accessory connector. The vintage air system is powered off the brown wire that would feed the "heater switch" aka the blower fan switch. I haven't had any problems to speak of. I can't see why a distribution block wouldn't work.

Landon, your setup is exactly how I want to do mine. Do you have any pictures of how you have the MSD box under the dash?

[juggernaut]

This is how I wired it in. Relevant information: I have a carbureted engine, mechanical stock speedometer and OER aftermarket stock tachometer. All connections are soldered and shrink wrapped with adhesive lined shrink wrap. NO butt connectors.

I repurposed the VSS wires to Distributor signals wires. I cut the twisted MSD distributor signal wire, soldered and shrink wrapped them onto the VSS wires, which are a twisted pair under the dash.

I routed the coil wires through the firewall connector utilizing the two open spaces. I purchased the AAW crimping tool and extra connector male/female spades. I had to remove the two screws from the fuse panel and detach it from the firewall connector to accomplish this.

I used the "BAT2" 30amp slot in the accessory connector for battery power and the "IGN1" 20 amp for the ignition power to the MSD box.

I cut the tachometer wire, extended it and connected it to the tach spade on the box. Unrelated to the MSD box, I had bouncing tach issues due to grounding issues on the instrument panels. I ran a ground wire from the back of tachometer directly to a chassis ground, that cleared up the issue.

I'll take some pics of the box mounting this evening.

9668396684

[tonyvol]

Landon, Perfect...Thank you for the excellent instructions and laying this out for me. The way you wired your car is exactly how I want to do mine.

Tony

[juggernaut]

Here's some installation shots. The glove box bracket is a aluminum I had bent at a local fab shop. I had to cut it in half in order to be able to remove the bracket without removing a/c box. It's not the best looking bracket but, it works.

967369673796738

[tonyvol]

Thanks a ton Landon. Looks really good. This is how I want to do mine.