alternator amperage

[chargerdon]

I have a 74 Challenger that from the factory had the 318 with the 907 auto and air conditioning.    What would have been the amperage rating of that alternator ?  I have seen anywhere from 45 to 60 amps specified. 

Today, i don't know if the alternator had been replaced or not, but its a square back with the two field wires.   How can i identify its amperage rating ? 

Reason i'm curious is that i'm thinking of adding a "pusher electric fan" to bolster the cooling capacity in slow moving parades that i sometimes drive the car in.  (right now i have the 22" radiator with 7 blade fan and a shroud.   it works pretty well, but, the temp definitely climbs in a 2 mile walking speed parade).    Im looking at a pair of 7" fans only because there is precious little room between the radiator support and the air conditioning condenser and the 7 in can be mounted a little to the side to gain clearance.   Ratings are for 800 CFM and draws 11 amp...and at idle speed i don't know if the alternator can put out 11 amp above the running of the engine and the ignition system.   

[RUNCHARGER]

Stock alternator puts out 41 amps when it is revved up a bit, not at idle. The stock alternator keeps the engine running at idle but not much more, the heater fan for instance will slow down a bit if switched on when the car is idling.
You'll be heading down a rabbit hole IMO, once you swap out the alternator then you'll be needing to upgrade the wiring and so on.
Not sure if a 22 inch rad is correct for a 74 A/C car, earlier ones had a 26 inch rad and shroud.

[chargerdon]

Your right...the radiator is 26 champion.   As far as wiring, i have already done a fair amount of wiring upgrade.   I.e...now running a 10 gauge wire from the alternator to the Starter relay, and removed the Ammeter and put in a Voltage meter instead.  Ive also completely removed the fuse panel and wired in a modern blade fuse box to replace the old bus fuses.   

If i do end up putting in the two 7" push fans, ill wire them directly to the starter relay with dash switches...as no need for them in regular traffic, and i'm thinking of putting in a 60 amp alternator.   Thanks for the info on the alternator...the shop manual simply says its based on the color of the label with yellow being only 34 amp...and the highest being 65 with a black label...but there are no labels on mine.     

[chargerdon]

Tested my alternator for amperage yesterday.   I have a Sun Amp gauge that i wired up with the alternator feed and turned headlights on for a few minutes to weaken the battery.   Then started her up...  at idle it barely moved off the 0 mark...maybe 5 amps and then revved her up and it went to 40 amp mark...   So...you were right 40 amps...   

Turning on headlights, AC, and radio plus foot on brake to turn on the stop lights, at idle my voltmeter i installed in dash was showing between 10-11 volt...so not enough amperage to handle the full load at idle...   

Real question is if i swap it out with an inexpensive 60 amp rebuilt alternator see: Part # 7509A at advance auto for $89.   Or Rock Auto https://www.rockauto.com/en/moreinfo.php?pk=1001389&cc=1078703&pt=2412&jsn=458&jsn=458 for 52 plus $11 shipping.  What im looking for is decent at 750 rpm idle..to be able to handle just the ignition plus two 7 inch pusher fans...so that during a parade i dont overheat...  Car is rarely driven at night... 

[BIGSHCLUNK]

I have a pusher controller and sensor just sitting if you have the need. Removed it when Bob at GLEN RAY 4 cored my rad. 

[Chryco Psycho]

Where is the timing set , often it will run much cooler with 16* approx at idle ?

[chargerdon]

Static timing is 16 degree, plus i use the manifold advance of 5 max so idles at around 21 degree...its where it likes it