Hang with me here for a minute folks. Listen to the essence of what I'm after. Tell me if you have experience doing this, or see major issues...

I'm wiring up my 57 Nomad restomod project. All fuse panels, relays, ECM (LS1), and most electronics/wiring is going into a custom center console that I'm building. Packed with wiring and components.

I want to keep the original "keyed ignition" on the dash. But one of the things I want to accomplish is to wire the starter circuit "outside" of the key ignition switch. In other words, don't want that heavy "12v red battery wire-to-purple starter wire" voltage/amp draw traveling thru the ignition switch. Want to use a heavy duty "relay" to energize (from the start position via the ignition switch) the purple wire to the starter. Via a relay I suppose? What is the appropriate relay to use for this. Is a 40amp relay "heavy" enough?

Another way of asking is how many amps pass thru the ignition switch when you turn the key to "start" and the starter cranks?

The starter itself is getting its voltage from a 1 ott stranded cable coming from the battery, so it seems to me the purple wire just "energizes" the solenoid on the starter that allows it to "pass" that 12 volts from the battery cable to the starter windings...

So how much draw does this (approx. 12 gauge) purple wire get? And what amperage relay is "too small" for that?

Stuck in automotive wiring theory hell right now. Can't seem to find the answers with google searches...