1987 - 1992 Ford F-150 Alternator Upgrades

So this weekend I noticed my alternator front bearing started making noise. Additionally I had some charging issues, which I am blaming on my starter solenoid, but I figure just to be safe I might need to replace the alternator. Looking on Oreilly's website the stock alternator appears to be around a 70 amp alternator, seems kind of small for a full size truck.....

Are there any super secret swaps for this that I should look into, or should I just go get a stock replacement? Anyone know of a bolt in that goes a bit higher?

karl check out rockauto.com they have 2 for about $70, but require you to mail back your core.


check out these I'm ASSuming they'll fit your setup.

i just so happen to have ur answer. The best up grade for the ford is the mustang 3G altenator. Its 140amp and is simple to hook up. just so happens i have one and the harness to go along with it.

http://fullsizebronco.com/forum/showthread.php?t=26658

x2 on what clarke said. I wasn't sure if the 87-91 came with them or not, I knew the 80-86 don't, and then the 92-96 do.

I don't know if it has to be mustang though, the alt on white truck is a truck part, 135 amps. Also, are you serp or v belt?

I gave you a ford super spank-off ambulance alternator with El Borracho. Just use that.

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Originally Posted by RCcola55

i just so happen to have ur answer. The best up grade for the ford is the mustang 3G altenator. Its 140amp and is simple to hook up. just so happens i have one and the harness to go along with it.

http://fullsizebronco.com/forum/showthread.php?t=26658

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What is different on the wiring harness, looked the same to me?

Also for Seth, it is a serp belt setup. Apparently in 93 they went to the better alt.

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Originally Posted by jerryg79

I gave you a ford super spank-off ambulance alternator with El Borracho. Just use that.

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I'll go look at it and see if it is a "bolt in"

I have the mustang 1996 alternator (140 amp) on my 1990 engine

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Originally Posted by 85cj7

I have the mustang 1996 alternator (140 amp) on my 1990 engine

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Does it bolt right in? Is the wiring the same?

it bolts right in, the wiring is slightly different but i'm pretty sure its just the pigtail.

which i have.

just go to O'Reillys, they should have a 140amp alternator on the shelf for your application...thats what BigRed had. I looked and looked for upgrades then just check the parts store, and...SURPRISE!

I need this pigtail to make the Mustang alternator work. Where do I get?

here maybe?

http://www.latemodelrestoration.com/...tor-Components

I put a 1995 Mustang GT 5.0 Alternator in the Klogger. For those that don't know, this is a Ford "3G" alternator. It puts 135 amps out at idle. It directly bolted to my 1990 F-150 5.0 engine. I did have to grind a tab off on the bracket.

At first I did not want to do this because I could not find a clear instruction set on how to do the wiring. Then I looked at the wiring diagram and saw how freaking simple it is.

All of this is well documented on full size bronco or Ford Fuel Injection.

Starting it up, I had 14.7 volts, when I pulled the negative off the battery it went to 15. I turned the lights and electric fan on and everything regulated.

Simple, easy, swap from 85 amps at idle to 135! :gigem:

good upgrade karl, the jeep has a 96 gt alternator on it, same deal.

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Originally Posted by 85cj7

good upgrade karl, the jeep has a 96 gt alternator on it, same deal.

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Ever have any issues? The interweb said the 3G's did not hold up to dusty/dirty situations?

replaced the alternator in dec. 06. haven't had a problem sense then.