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Presently restoring '72 pre L, 3639. Will be modifying the ignition system (Duraspark II), headlight & fan circuits (as published in this section of the forum posted by George P. in response to Bruce32751, posted March 3, 2008. (unable to display diagrams of this closed topic)
Need clarification on the following:
1.)Duraspark II schematic refers to "new fuse" between starter relay & new SPST relay: The SPST relay is for 50 amp rating. What amp rating is recommended for this "new fuse"?
2.)In the Revised Headlight Diagram, two relays are inserted in the wiring schematic: What amp rating should these relays have?
3.)In the revised Fan Circuit Diagram, two "new fuses" are wired from the load side of the ammeter to two new SPST relays: Again, what amp rating should the fuses and relays have?

My thought is to have, at least, the amp rating of the fuse circuit I am tying into; however, clarification would be greatly appreciated.
Thank you
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I use 20 amps per headlight, 20 amps per fan, and 20 amps for the ignition.

Nothing scientific in my choice. I never measured the branch currents. I know 20 amps gets the fuses out of the way of normal operation, they are basically there as safety devices in case of a dead short, preventing an electrical fire.

Be aware I revised the ignition power circuit since 2008 to energize two relays (in parallel) instead of one. One for the ignition as before, and a second for the electric choke.

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