100 Amp Alternator/Part Selection Help

Lance Hogan · #1 (**permalink**) 03-20-2008, 10:25 PM

I have a 390 V8 which I am installing in a 1955 F100. I recently ordered a PowerMaster 100 amp one wire alternator from Summit Racing (part # pwm-8-37101). After receiving and attempting to install the alternator, I noticed that the back of the alternator rests directly on the head preventing the water pump pulley and alternator pulley to properly align. I have the alternator installed in the “upper” location, as I want to use the room below the alternator for my AC compressor. I called Summit to discuss this issue and they recommended returning the alternator. I don’t understand how the original alternator, which I have, bolts in perfectly and the PowerMaster unit does not. Does anyone know of a 100 amp alternator that will directly bolt into the stock location that properly aligns with the water pump pulley? Any advice or guidance is much appreciated.

Respectfully,

Lance

OrangeJuice · #2 (**permalink**) 03-20-2008, 10:36 PM

Could you maybe have a 60 amp alternator built to 100 amps. There's a shop around here that can build them up to what you need.

Hope this helps.

Freightrain · #3 (**permalink**) 03-21-2008, 09:56 AM

Yes, if you have a local shop, they can upgrade your stocker. They can even convert to one wire for you.

I run GM one wire's on two of my vehicles(FE powered). I custom mounted them on lower RH side. I know that you have issues since you want your A/C to be there. I hang them from bolt hole in front of head, then make small adj bracket off lower timing cover bolt. Simple and effective.

Lance Hogan · #4 (**permalink**) 03-21-2008, 12:05 PM

Orange Juice & Freightrain,

Thank you for the quick replies. I am new to the area (east central Illinos) and will check around for alternator shops that can possibly upgrade my stocker.

If I can’t find a shop capable, do you think a stock alternator (61 amps) would be enough to handle my electrical needs for my truck? I will be running A/C, power windows, and radio.

Freightrain · #5 (**permalink**) 03-21-2008, 01:35 PM

I can't see why not. The only thing that will really draw is the a/c fan and the radio(if it's a big boomer style). The windows are a random draw that won't really affect much.

It wouldn't hurt to upgrade, but you might get away with the stocker for a while. The place you might notice it if you idle alot with a/c fan on HI and radio going. You'll see your lights be dimmer then when you are on highway at speed.

OrangeJuice · #6 (**permalink**) 03-21-2008, 03:23 PM

If you have your stocker built to handle 100 amps you will have to use a heavier cable from your alternator.

sapperken · #7 (**permalink**) 04-14-2008, 03:54 AM

I had the same problem with summit's powermaster alt. I returned it, and got the correct one!! If you call them and have them call powermaster you will find out the Part # in the catalog and online is incorrect, they only offer a 150 and 200 amp alternator for our vehicle. And both of which will rest with the rear of the alternator resting on the head. I have had mine like this for awhile now and no issues yet.

When you get your new correct Alternator from summit you will see it is within 1/8" of the OEM alternator, unlike the one you sent in, I am guessing that was almost 1/2" bigger, mine was. But call them tell them to crossreference it with powermaster.

Powermaster, if you call them directly, offers a direct replacement 150-200 amp alternator, that is the exact same as the one you took off. But I tell you now, it is a hefty price tag sitting at around $300 when I called them over 3 months ago.

I opted with the 200Amp oen wire kit from powermaster (via summitracing) and it was only a fraction of the price, but, still rubbed only slightly on the head.

Good luck.