Hi , I am building a new motor for my 86 F150 , a 351w to 385 ci , 74 block 1990 front serpentine drive and A/C etc it has a 2G alternator i think and want to upgrade to the 3G i have heard there are two types with different bolt centers can anyone give me the right number that fits my 1990 f150 brackets .
Cheers .

 

Hard to say, I am dealing with the same thing on my '82. There are two different things you have to consider. first is case size, there is a small case 95A alternator, then there is the large case 130A alternator. Then there is a 7" pivot mount which is what you will use with a serpentine belt setup from what I have read, then there is the 8" pivot mount which is supposed to be for V belts.

Some plates cite the 95A 3G has a 7" and 8" pivot variants but every alternator shop I talked to said they never had a different spacing for the 95A. The 130A does how ever.

 

Maybe i could queston amazon or rockauto before i order , i just measured my 2g and its 7" centers . Cheers

 

All forged 385w motec ecu

 

Yep serpentine is a 7" centers so you can get a 95A 3G and it will work.

This is one 7" pivot mount option that will bolt onto your mount.

https://www.dbelectrical.com/product...-302ci-v8.html

This is the one I am looking at for my truck as I need the 8" pivot for my V belt equipped truck.

https://www.dbelectrical.com/product...-92-93-94.html

You wont be able to run this one as its the 8" pivot but if you wanted 130A there is a 7" pivot with 130A output which is this one here.

https://www.dbelectrical.com/product...bus-92-99.html

 

Thank you , thats great , for the price difference 130a will be nice , ecus like good power . . Now we need to get rid of this Virus and get you guys back to work so i can buy some parts . Cheers.

 

130A is good if you have a serpentine belt that wont slip. it sucks if you have to run 130A and have a V belt.

 

I'm using a 3G with a single v belt and upon start up the belt would slip and squeal. Changed the regulator to one that has soft start ( allows amperage to increase slowly for a few seconds ) and took care of the problem. My truck is bare bones with no A/C or power anything so I really didn't need the 3G. Only changed it to get rid of the plug in connector that fails on the 2G.

 

Here's a handy reference with PNs and applications: 3G Conversion - Gary's Garagemahal (the Bullnose bible)

 

its decent but isnt all that handy since he just deleted all the 95A reference.

 

Hi Rusty , thanks again for the 3g alternator link , i see that listing is for large trucks and on that photo if correct shows 2 vee pulley , do you know if the 7" center lugs is the same as a 95 mustang 130a, nice bosch one at rockauto?

 

For the large case 130A 3G alternator one way to tell if its a 8" or 7" pivot is by looking at the threaded ear. the 8" pivot has a recessed cut into the ear with a reinforcement bar. The 7" pivot does not have this recessed cut into the ear and the ear mounts close to the case.

 

Thanks , you would think with all the retro fitting of parts , this measurement could be included in the specs . Cheers

 

I have a 95 mustang 3g and it is 7'' centers

 

Excellent , i will order one ..