Possible to have 2 different alternators?

[kensousa]

'71 C10 short/fleet.
We have reason to believe it was a government issue truck due to a metal plate inside the glove box with a government serial / issue number.

The first picture is of two gizmos that are on the engine bay firewall, driver's side just above the bulkhead connectors. I can't find them referenced on any of the schematics that I've seen.

Second picture is an extra connector that I have and looks to me like a later model alternator connector? Those wires appear to originate in the two gizmos discussed above.

And third picture, I already have the stock alternator installed with the factory external voltage regulator.

Has anyone seen this before?

[Southcity]

I have not personally seen it but have heard of it on trucks of this time for fleet vehicles (i.e. electricians, welders) tow trucks (wreckers), emergency vehicles, etc., to help power auxiliary equipment.

[HO455]

I believe your looking at parts of the transmission spark control system that came on 71's. See link..
It may have only installed on trucks sold in California but I don't know that for a fact.

http://67-72chevytrucks.com/vboard/s...d.php?t=750604

['68OrangeSunshine]

HO455 is right, the spaced connectors in pic 1 are for the TCS. An obsolete emissions control device that's best bypassed.
The connector shown in pic 2 is for the next generation alternator. Possibly used in tandem with the stock alternator to generate 24 Volts which is the power for military radios and other equipment.
Pic 3 is the stock '71 alternator used with an external voltage regulator.