This is an easy and prudent safety modification for 65-66 Mustangs. Relying on a single bowl system may be original but is not safe. This kit makes changing to a safer dual bowl system very easy. The instructions aren't as good as the kit. They're written as though the drum and disc brake systems were the same, which they are not. Also, you will need to tweak the hardlines and the stainless tubing is REALLY STIFF. I like the standard steel lines. Use a plier-type tubing bender for a nice fit.