alt question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

76bonanza · 12-03-2005, 04:41 PM

Right now I have a 63 amp 1 wire alt looking to up it to 100 amps due to future amp and electric fans. First question is there any thing I need to do to the wiring with a larger alt? Second are any of the alt in summit or jegs any good? We have a local shop that does good work could he rebuilt mine and up the amps? Also will using a larger alt affect anything badly? I may not put the fans and amp in for awhile or will the truck just use what it needs and the extra is ok(don know if that even made sense.)

dwaite72lnghrn · 12-03-2005, 07:45 PM

If your present alt has 12 gauge it should be ok. you might want to go to 8-10 gauge from the alt to the connection on the fender where the fusible link is. You might want to upgrade the fusible link to take the higher current. The alt if it is good will only provide what is needed when it is needed. Any alt "CS" from GM fullsize truck will put 105 amps, They went to this to keep the vehicle running at idle because the old style had no output at idle and the new style has upwards of 40+ amps at idle.
If some one local can rebuild yours for higher output and warranty it I would go that route. Never delt with summit or jegs so I can't help you there. I went with a GM alt.

Aquivarious · 12-03-2005, 07:52 PM

When I switched the stock alt on my old truck from stock to 150amp, just swaped them out with the same wires and it worked fine. And i would buy it local, they offer warranties.... and its easier if they want a core to just hand it to them...

12-03-2005, 04:41 PM	#1
76bonanza Senior Member Join Date: Mar 2003 Location: St robert Mo Posts: 2,001	alt question Right now I have a 63 amp 1 wire alt looking to up it to 100 amps due to future amp and electric fans. First question is there any thing I need to do to the wiring with a larger alt? Second are any of the alt in summit or jegs any good? We have a local shop that does good work could he rebuilt mine and up the amps? Also will using a larger alt affect anything badly? I may not put the fans and amp in for awhile or will the truck just use what it needs and the extra is ok(don know if that even made sense.) __________________ 1968 c10 lowered 3" 4" 355/Th400 built by Hatfield racing in joplin MO

12-03-2005, 07:45 PM	#2
dwaite72lnghrn Registered User Join Date: Jun 2002 Location: central pa Posts: 1,525	Re: alt question If your present alt has 12 gauge it should be ok. you might want to go to 8-10 gauge from the alt to the connection on the fender where the fusible link is. You might want to upgrade the fusible link to take the higher current. The alt if it is good will only provide what is needed when it is needed. Any alt "CS" from GM fullsize truck will put 105 amps, They went to this to keep the vehicle running at idle because the old style had no output at idle and the new style has upwards of 40+ amps at idle. If some one local can rebuild yours for higher output and warranty it I would go that route. Never delt with summit or jegs so I can't help you there. I went with a GM alt. __________________ 72 longhorn c30 502BB/th400/fact air/4.11rear/ custom camper 72 bug(the better half's) under reconstruction 2009 HHR aqua blue 71 GMC k20 350/sm465 2009 Chevy hd3500 6.6 Victory Red crew cab dually Dave & Jeanne

12-03-2005, 07:52 PM	#3
Aquivarious Registered User Join Date: Sep 2005 Location: Alton, Illinois Posts: 90	Re: alt question When I switched the stock alt on my old truck from stock to 150amp, just swaped them out with the same wires and it worked fine. And i would buy it local, they offer warranties.... and its easier if they want a core to just hand it to them... __________________ '71 Chevy C-10 SWB (Project) '04 Mazda RX-8 (F*** around Car) '85 Chevy C-20 (Former Project) Currently Serving In IRAQ. (Man it sucks over here..)



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