Looking to replace my temporary (old) alternator with a re-build unit. The previous unit I on the car died when the retaining screws loosened up and allowed the 2 halves to spread out just enough to mess things up...it was the wide-body stator style alternator.

Focusing on the Bosch ones, AL504X & AL502X...RockAuto has a decent price and I just got a discount code email from them...but I can't for the life of me figure out what difference the stator thickness makes, and unfortunately neither Bosch, nor their resellers show a different AMP rating for these units.

The bodies of the alternators look somewhat different, not sure if this is pure 'cosmetics' or whether the changes were due to load carrying capacity, better cooling, etc, etc...

Here is what I'm talking about:

AL502X


AL504X


I'm not looking to replace the 'stock' look with a shiny part either.

I admit, I am no electrical marvel...LOL..heck, I barely get by...so I'm hoping there is a very simple explanation.

Not cosmetics & it appears that the later one with the thin stator has thicker case halves to make up for it so the alt will physically direct bolt in interchange. Unless someone here is up on Bosch (I ain't) I would email em or easier (faster) would be to call a local alt rebuilding shop as they would (very likely) know. Likely (& k.i.s.s.) it'd just be a higher amp output alt (later improved technology)

504x 55 amp
web page

502x 60 amp
web page
The 60 amp may be the later variety with dual field control but will work with the included jumper

Thanks guys...here are a couple more links I came across as I plugged away in search of the understanding of 'alternator power output'...lol

1) EngineBuilder Magazine Article

2) National QuickStart - parts, upgrade, resto business

These guys in particular have the higher power stator setups...actually considering picking up their 80 Amp kit...seems like a better solution to fix my current alternator by upgrading it...what actually broke was the stator winding=>screw clip...