Holley 550-407, Installation Manual, Page: 15 / 54

15
13.1 Ignition/Engine Speed Input Wiring
OPTION 1
– “Coil -” –
Option
one uses the “Yellow Wire” for engine speed input. The yellow wire is a loose wire located 52” from the
ECU connectors. It is bundled with several other loose wires. The following two diagrams show how to wire to the two most common
applications which are:
1) Any General Motors engine equipped with a factory large cap HEI distributor equipped with mechanical/vacuum advance (Figure
17).
2) Any engine equipped with a factory mechanical advance distributor and separate canister style coil. This would include any
points style distributor (Fig. 18).
Figure 17
below shows how to connect to a large cap HEI distributor.
Figure 17
Figure 18
below shows how to connect to a factory style ignition with a canister style coil.
Figure 18