Re: Stereo and Amp install
My recommendation would be to attach to the horn relay, with a fuse close by. Definitely want a fuse on a heavy gauge wire before it passes through sheet metal that could easily cut the insulation and cause a short and subsequent fire.
If attached to the starter solenoid, the fuse should be close and in the engine bay, before the wire breaches the firewall.
1970 Chevelle Malibu, one family owner
355 SBC, XE262H cam, Performer RPM heads, MSD HEI, TH200-4R trans, 3.55:1 Posi, digital gauges