the ecu

[twinturbo]

if your using carbs there is no wiring or ecu is there not?
the engine uses coil and points - points can be replaced with optical

Depends on yourset up,
If your using something to controll your spark, say, megajolt, then you need wires to the TPS, air temp, coolant temp.
But if you were to use a dizzy, then no, no wiring?
(I probably havent made that very clear)
Hope it helps abit

Not so, all sierras have at the very very minimum had transistorized ignition amplification. Most carb models run a variation on ESC ( electronic spark control ) which makes things a little more controled.

No such thing as Points on a sierra unless you go and fit a capri or tina dizzy to a pinto.

CVH and DOHC just have HT distributors with no spark timing control built in. They do need either their correct ESC or EDIS control. or third party spark control

The wiring is easy if you keep the engine loom.

TT