1974 c10 wiring nightmare please help

[belair327]

ok guys i took a 305 out of a early 80s  and put it in my 1974 someone was nice and cut the starter wires on the 74 i had a larger red wire i knew went tyo large post on starter a purple wire  i know went to small post on starter had to yellow wires i was told goes to big post on starter and the motor im using has hei so i hooked the hot wire to batt side of dis heres my problem i started the truck it ran went to shut it off turned the key and the truck stayed running so i unplugged the 2 wire plug in on the alt truck turned off so now im lost i can turn the key on and turn on like the blower motor or the turn signals and then turn key off and that kills power to them so im thinking the key is working right so next thing i checked was pulled the 2 wire plug on the alt one of the wires has power at all times no matter if key is off or on can anyone have any ideal what im missing

[VileZambonie]

Welcom Belair327. Slow down when you are typing and try to use punctuation. It makes it that much easier to try and understand what you are saying.

What was in the 74 before you put the 305 in it? Was it set up for points or HEI? On the starter solenoid you should have the Battery positive cable, two fusible links and one wire going to the S terminal (purple). Do you have 12 volts using a meter on the coil wire or is the resistance wire still connected? Does the instrument cluster have an ammeter, volt meter or warning light? You may need to integrate a resistor. I've used the 10Ω 1 watt resistor like described in this article.

http://www.rowand.net/shop/tech/AlternatorConversions.htm

[belair327]

sorry i have no ideal what was in the truck before.The truck had gauges not warning lights.there was just one wire that came out the firewall that i hooked to the dis.I dont have a volt meter to check anything.Is the 2 wire plug that goes into the alt is one of those wires hot at all times?Mine is wether key is off or on ,im lost

[1980c10]

It kind of sounds like you have your starter wires mixed up, you need a switched source of power for your dist, study the wiring diagrams and try to make them right again. It sounds like someone has made adjustments. Guessing will make matters more frustrating.

These should help;
 

[belair327]

anyone have a real good wire diagram?

[devanray]

Hey belair327, welcome. Wiring can be a headache, but if you take it slow, follow one wire from the beginning to the end, it ends up not being so bad. Label as you go.
One thing that has helped me a ton on this site is to use pictures, don't over do it, but take four pics and if you can label them in MS Paint or some similar program. That way when you say "2 wire" people can look at your pic and see exactly which wire your talking about.

http://forum.73-87chevytrucks.com/smforum/index.php?topic=11766.0

This link will lead you to a page full of wiring diagrams (providing by our fearless leader), you may need a few different ones to piece this puzzle together. Take your time, post some pics and spell/grammer check (it really helps others help you)

Oh, and buy a meter, it is going to be very tough without one.

[1980c10]

Thats what I tried to link..

[devanray]

You might have copied to much, it looks like a dead photo link. But as long as he gets it.

[VileZambonie]

Do you have a volt meter or ammeter in the instrument cluster? Where are you located? Maybe someone here is close enough to lend a hand otherwise you should invest in a digital meter.

[VileZambonie]

If you look at this wiring diagram (it's a simplified diagram), You can see cavity B or 1 shouold have B+ with the key on when you have the connector disconnected and no B+ when the key is switched off. If that is OK you either have a shorted diode in the alternator or you need to install the resistor as posted above (assuming everything is hooked up correctly). A meter would really help.

[belair327]

ok my friend i have one more thing to ask u then no more.is the wire that goes to the battery side of distribator is that wire hot at all times?thankyou for all ur help!!!!!!!!!!

[VileZambonie]

It needs to be key on 12v however the factory 74 system used a resistance wire. If you're using an HEI you need to run a new circuit less the resistance wire.

[1980c10]

Heres another helpful diagram; and good info all around this site;
http://www.chuckschevytruckpages.com/underhoodwiring.html

[autorepr]

Just a thought....... If the alt is back feeding and keeping the ignition on in a truck equipped with gauges a guy could install a light bulb in series in the ignition feed at the alt regulator plug. It would light up at first when the truck is started and go out when the regulator turns on and the alt starts charging just like the light on the dash if equipped with idiot lights. The bulb would activate the alt. but not flow enough current to run the ignition so the truck would turn off fine with the key. (I know "that's what the diode does")

[VileZambonie]

That's what the resistor I linked above would do IF his feedback is from a shorted diode but yes you are right and the use of a test light in series would reveal that.