alternator help asap

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Jul 13, 2010 | 09:51 AM

SuperDutyScaler

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From: South Jersey

alternator help asap

OK i have a 78 f-150 4x4 with 351M and C6 that now has a 77 f-150 2wd body on it. i used the 77 wire harness because it was in better condition than the 78 harness. problem is i have everything back together now and I'm ready to drive it except for one problem if i hook the alternator wires up to the truck my alternator is pulling [power even when its not running. its also not charging either. my question is do you wire the truck different from 77 to 78? or is my alt. just shot? i really don't want to buy the same alt again id rather go th the Chevy one wire hook up and get rid of the voltage reg also. problem is i have no idea how to do this so i need allot of help. can someone tell me what Chevy alt to buy and show or tell me how to hook it up and get rid of the voltage reg.

Jul 13, 2010 | 11:13 AM

c.l.nye

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have you thought about a "3G" alt. upgrade? It is a nice upgrade for these old beasts. I did one on mine a couple months ago and love it. you can do a search for "3G alternator upgrade" and find a wealth of info.

Jul 13, 2010 | 01:23 PM

SuperDutyScaler

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From: South Jersey

whats a 3g??? i just bought a chevy one wire alt

Jul 13, 2010 | 01:50 PM

79FordBlake

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From: Wingo, Ky

If im thinking about the right alternator the GM alternator is not a one wire alternator. You have to have a battery wire and you have to run a sensing wire and an exciter wire. Which is easy to do, I was just bringing it up.

Jul 13, 2010 | 02:08 PM

704 dentside man

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A 3g setup is the way to go. I have yet to do it on any of my rigs, but I'm waiting for an alternator to start acting up and then it will happen. The 3g alt is from a later model Ford...I can't remember which vehicles to pick from at the moment, but there are several. The 3g is a more efficient set up and I believe there are a few different power levels rangin from 95amps to 130amps. Alot of guys just pick a junyard alt for under $20 and go on their merry way.

Jul 13, 2010 | 02:49 PM

RangerHaywood

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From: Mount pleasant, michigan

Hey now that you mention it, now i sorta wanna do this! So if i got one, for my 78 150 4x4 351m, would it be a bolt in replacement, and how would i wire it up? i would wanna get a 130 amp i think for all my fog lights and subs

Jul 13, 2010 | 02:58 PM

jsutton

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Joined: Sep 2003

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From: Northeast LA

Here you guys go, this thread is awesome and the link in it to the fullsize bronco thread is great too.

https://www.ford-trucks.com/forums/9...g-upgrade.html

I'll be doing this hopefully when I get back from vacation next week.