Best alternators:

[VileZambonie]

You can all be brand loyal but in reality that doesn't make a lot of practical sense (for more reasons then I care to discuss right now) but what does primarily is availability on your parts. Most AP stores offer decent warranties on alternators and will have these in stock. If you think an AC Delco alternator won't let you down, think again. If you are ordering it from rockauto or the like and it decides to find the cemetery are you okay with waiting a few days for a replacement and then waiting for a credit? It sure is nice to pop two bolts and run down to the parts store and be back up and running in no time. If that doesn't matter to you then what I said is irrelevant to you but for those who daily drive and rely on your trucks, availability and warranty should be helping you decide where to buy those parts.

[FlatBlack77]

Very well said Vile

[hatzie]

You can all be brand loyal but in reality that doesn't make a lot of practical sense (for more reasons then I care to discuss right now) but what does primarily is availability on your parts. Most AP stores offer decent warranties on alternators and will have these in stock. If you think an AC Delco alternator won't let you down, think again. If you are ordering it from rockauto or the like and it decides to find the cemetery are you okay with waiting a few days for a replacement and then waiting for a credit? It sure is nice to pop two bolts and run down to the parts store and be back up and running in no time. If that doesn't matter to you then what I said is irrelevant to you but for those who daily drive and rely on your trucks, availability and warranty should be helping you decide where to buy those parts.

Very good point.

If this is your daily driver or a rig with uncommon parts like my green iron then the game changes significantly.  'Swhy I get those done by a local guy that I've known and trusted for years. 
When I brought my run of the mill Delco SI from my 85 C10 and the CS from my 2000 6.5L to him he said don't bother just get a Delco Pro series reman online and hang onto the cores.  He's had difficulty in getting parts made outside Asia for quite a while but he seems to still be able to get decent quality parts.

My 85 is my only gasoline engine pickup and is not a daily driver.  I've had fairly decent experiences with RockAuto warranty items. Three days in the unlikely event of a warranty claim isn't a deal breaker for me.  It could be for some people.  If it is change your game plan.

[Irish_Alley]

im with vile also on the parts stores and getting a replacement. back when i got my truck back on the road with the built alternator straight from the alternator shop, a month later it failed. i was about 4 hours away from that shop (it was a one wire alt and would start charging at 300 rpms). and it was the weekend so no alt shops would be open to get me back on the road by monday. luckily napa was around this town and i left all my wires for the stock alt alone so i was able to just get one from there. took the bad alt to the alternator shop where the warranty would only cover parts and he rebuilt it.

so now i drive around with this rebuilt alternator in my tool box cause im stuck with two good alternators cause

[philo_beddoe]

Plus avoid return shipping charges, makes sense to buy what you can local. Anyone know an AP srore that sells the delco-remy alt?

[75gmck25]

My '75 GMC had A/C and HD cooling, so the alternator was a 63 amp V-belt 10si unit.  I replaced it with a 94 amp V-belt 12si unit from a mid 80's Chevy.  Its a direct bolt on, and the only change you need to make is to upsize the charge wire from the stock 10 gauge to an 8 gauge.   I think the price on a rebuilt 94 amp unit was nearly the same as the stock 63 amp.

I also ran the charge wire directly from the alternator over to the battery positive, with a fusible link on the battery end, instead of using the starter terminal as a junction point like GM did from the factory.

Bruce

[rich weyand]

You probably have a 10SI on there.  It has the stamped impeller for cooling on the front.

You can switch to a 12SI with no wiring or bracket changes and go a lot higher.  90+ amps is easy.  Summit has 12SI-format alternators to 200 amps, which is way overkill, and you pay big bucks for it, so I don't recommend it.

Here's what I did:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=28215.0

[Stewart G Griffin]

Need more help:

i have the hybrid belt setup of water pump and alternator having the ribbed serpentine belt.  And everything else is conventional V-belt.  The ribbed belt is, i believe 5 rib?  And the pulleys are i believe 4 grove?

Basically this setup, if you'll scroll down:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=21823.15

Both AC Delco and Remy list alternators with a V-belt pulley for an 85-86 4.3 application.

Pretty much all the parts stores also list alternators with v-belts for this application.  (Even though if you search for alternator BELT on their websites, they list ribbed belt..............)

Can anyone come up with a workable part#?   The plug is at the 12:00 position.  i would like to keep it under 78amps, 63 preferable.

i know we can just change the pulley, but i don't have the tools/ability to do so now, so i would like to keep simple with a bolt on part.

[Stewart G Griffin]

P.S.
i came up with AC delco 321-357, which is the part# for an 87 R10,  but does this alternator turn CW?   Did the 87 trucks have the full serpentine setup?

[bd]

That alternator should work fine.  It is CW rotation.  The B+ output post should be clocked the same as the adjuster bolt and the regulator plug just CCW from the post, looking from the front of the alternator.  The 87 R10 used a setup virtually identical to what 78 Chevyrado imaged.

[Stewart G Griffin]

That alternator should work fine.  It is CW rotation.  The B+ output post should be clocked the same as the adjuster bolt and the regulator plug just CCW from the post, looking from the front of the alternator.  The 87 R10 used a setup virtually identical to what 78 Chevyrado imaged.

Yes, after doing a little more research, it appears that the true serpentine didn't start until 88?

[Stewart G Griffin]

For a starter, i went with REMY 28367 which was $25 at Rock auto.

Why so cheap?   i'm not complaining about the price, i am just concerned----that it may not be high quality at such a low price...?


2) it turns out that the alternator may have not been the problem, although the new one works great and i could have probably used a new one anyways.

[Irish_Alley]

stew maybe you should start with whats wrong and what test youve done so far

[Stewart G Griffin]

The starter all of a sudden last week would sometimes not crank much, after a few tries, it cranked normally.   The situation repeated itself a few times.

Battery tested good

Charging system tested bad/"underachieving", so replaced alternator with the ac delco  321-357

Starter problem still persisted.  To me, this indicates bad starter-----you try it a few times, bad crank, then on the third or fifth time normal crank etc.

[hatzie]

Before you toss the starter...  Check the battery voltage and then all of your connections at the solenoid, battery, and alternator bracket.