I Might Just Know What I'm Talking About
Join Date: Jul 2001
Location: Sisters, Oregon
Thanked 1 Time in 1 Post
Re: BIG step in my SBC conversion
You should find that the bulkhead connector is split into 2 halfs- one half is for the lighting/horn/ect, the other half is for the engine controls. From this half you need to determine which controls on your replacement engine are also on the old engine. I did my 350 swap into an 82, but things should be somewhat similar. The HEI distributor wire requirs one hot wire-preferrably 10 or 12 ga, for power when the key is in on or start. The starter requires one thin wire, hot in the start position, and the battery cable. You will have the oil pressure sender, the coolant temp sender, each a thin wire to feed your gauges. The alternator has a hot wire to the battery, and a thin wire feeding back into the cluster. If you have an electric choke, another hot with key on wire is required. If you can find a factory wiring diagram, finding which wire performs these functions on the old engine, and using them on the new engine, is optimal. Lastly, the fuel pump. You're going electric? The OE pump is too high pressure/flow for a carbureted motor, an aftermarket electric can be wired into the old circuit, and the pump can be removed from the tank and replaced with a bypass hose, or a mechanical pump used. As for the excess wires, bundle them securely, and tuck them down in the black hole underneath the brake booster. Or selectively remove them. This is all easier if you use aftermarket mechanical gauges and a cable driven speedo. If your current speedo does not use a cable but a speed sensor, be sure to leave the wiring for that intact.
If you are capable of performing the mechanical end of the swap, then the electrical end is just alittle more learning, and careful execution of plans. I definately would use the factory wiring, even if you only use a quarter of it, as opposed to replacing the whole thing.