The 43 Amp 10si in my '75 98 is on it's way out and I'm looking for a high-output (at least 100 Amp) replacement that will bolt directly into the factory brackets and use the factory harness.

I know there are plenty of high-output 10si units out there, but from what I've read they are known to burn themselves up due to inadequate cooling for anything over 80 Amps.

Anyone have any recommendations? Are there any CS style alternators out there with the rear bolt hole in the correct location for the older brackets?

 

Does the car have extra non-factory electrical loads? 43 amps is kind of light but 100 amps isn't needed unless there are additional non-factory loads. Point is if 100 amps aren't needed a 10si with much higher output than 43 will get the job done well.

'75 98...what a nice cruiser. Parents had a triple silver Regency sedan.

 

The alternator will put out the amount of current that is needed by the electrical system. Since you currently have a 43 Amp alternator, I am guessing that is all your system needs. So if you have a 100 Amp alternator and your system is needing only 40 Amps, then the alternator won't burn up due to insufficient cooling.

 

A 12SI 94 amp would probably be the easiest and redily available direct fit alternator to use having the rear hole line up.

 

^^^THIS. 94A is about the peak output for a factory 12SI. I like to use the version from a 1986-87 Olds Custom Cruiser with 307. ACDELCO 3342305 or REMY 20269, both in the $85 range at RockAuto. If you really need 100A or more, use a CS130 from the 1989-90 Custom Cruiser with 307. ACDELCO 3351011 or REMY 91310, both rated at 105A. The Delco version is about $75 at RA, the Remy slightly higher. The two part numbers I provided come with a V-belt pulley and have the correct mounting ears to bolt to your existing 10SI brackets. I run one of these on my 62 F85. You can get a conversion jumper that lets you plug the CS130 in without modifying your harness.

 

Any wire upgrades needed for the increased amperage output?

 

x3
12si is the easy answer.

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^^This^^
Unless you intend to run a 50 amp motor home HVAC in the trunk....

 

Upgrading the charge wire (the wire from the alternator stud to the battery) to a 8 gauge might not be a bad idea.


Inspect the wiring, if it’s good you will more than likely be ok.