Electronic Ignition (HEI)

Three ways to go electronic: (1) almost any late-model Pontiac HEI distributor (e.g., from a 1977 Trans Am); (2) a points-replacement kit (Mallory or Accel) that converts your existing distributor; or (3) a full aftermarket electronic distributor (Mallory or Accel).

• Fit (check before buying): firewall clearance is tight — many cars fit fine, some need the firewall tapped in ~1/4–1/2″ (especially if you add an Accel Supercoil). First check your body bushings and subframe position; worn bushings or a rearward subframe cause the clearance problem (modify the firewall with the engine out, using a block of wood and a hammer). Best to borrow one and test-fit the cap before buying. A Mallory Unilite (stock-looking, red cap) is a good alternative, especially on a 4-speed car.
• Keep it reversible for show: rather than hacking the resistor wire, solder a parallel #16 wire to the same firewall-junction terminal and tape off the old one.
• Install: re-gap the plugs (~.045–.060″), use thicker plug wires (needed for the HEI cap), and use di-electric grease (new units include it). Prefer a genuine GM HEI over an Accel clone.
• High rpm: GM HEIs drop current above ~4600 RPM — use an aftermarket HEI-style distributor if you rev high.