Originally Posted By ahy
First step is to figure your loads... and go from there. Ignition, fuel pump, fan, lights, AC?, accessories. There are posts in the archives to help with "standard" loads.

An electric fan pulls a lot of amps and the fan is mostly needed in traffic or low speed which means idle RPM. You need lots of alternator idle output with electric fan.

As far as what to run, it depends in part on weather you are running AC. A 120 amp Denso can be retrofitted pretty eaisly with "non AC" setup. "With AC" needs specific brackets which do not fit the Denso or other alternatives so well.

There are 140+ high amp alternators available from Powermaster (GM based) though these may not fit well with BB and AL heads. "No fit" in my case with a BB and Edelbrock heads.

FWIW I run a BB with EFI, big fuel pump and mechanical fan. With the big fuel pump + electronics, a 75A (max) output alternator could barely keep up running and big discharge at idle. I switched to the "big Chrysler" alternator from a '78 Cordoba (100+ amps) and it does fine. Just heavy.

With electric fan I think you need 120+ amps output and good idle output.

I may switch to a Quality Power unit to save weight (link below).It promises to install same as a "square back". Just a little spendy.

Whatever you do, please post results.

http://www.qualitypowerauto.com/item_557/Chrysler-Mount-Mega-Amp-Alternator.htm



What your calling the squareback is that like the original that would have came on my car. I called powermaster and you're right they had nothing that would fit my car with high amperage without making special brackets to make them fit.