I am looking at putting a chrome alt on my '73 but have been told I will have to rewire some items if I go with a 100 amp since mine is a 42 amp output. Is this true? I am shopping at Summit and can't find a smaller one in chrome.

I m curious,what items would you need to rewire? I put a Summit Racing 100 amp chrome alternator on my 81 ,because of additional elect. drain accessories,I ve had no issues at all.

Supposedly, the wiring for the output goes through the charging gauge and even an upgrade to a 100 amp may blow out the gauge. My oem is a 42 amp output, what is your '81?

I m curious,what items would you need to rewire? I put a Summit Racing 100 amp chrome alternator on my 81 ,because of additional elect. drain accessories,I ve had no issues at all.

BTW, my amp gauge tops out at 40...

is the 73 gauge in amps or volts? I can t remember what year when it changed.if its amps, then you probably need to change the gauge, mine is volts, shows about 14.8 volts, running.....my orig alt was 60 amp ...I think Jegs has some 60 amp chrome alt for chev

I guess you posted that while I was typing..one finger method..so you could change out the gauge to newer model, using the 100 amp, or, I think I ve seen just chrome housings kits on Jegs for about 40-50 bucks.

I just looked, Jegs still sells them.. just swap out the housing on your present alt.. http://www.jegs.com/i/JEGS+Performance+Products/555/10150/10002/-1

I just looked, Jegs still sells them.. just swap out the housing on your present alt.. http://www.jegs.com/i/JEGS+Performance+Products/555/10150/10002/-1

It's an amp gauge and tops out at 40. Is it possible that I can get away with a 70 amp without changing the gauge? The 42 amp thats in there never gets over 10 or 15.

that I can t say..try it, if it burns up gauge, then update it..or You could use a larger pulley on alt. to reduce the output some..

I'm not sure on this but I think you have an externally regulated alternator. Are you changing to an internally regulated Alt.? If you are, then you need to do some re-wiring with the Volt. Reg. I converted a '72 Buick GS to an internally regulated but wanted to retain the factory look, so I added some jumper wires in the external regulator. The Amp gauge will be a problem if it's only rated for 40 Amps.
I used a "PowerMaster" 100 Amp chrome Alt.Check them out on the Web. Nice stuff!:bump2:

I'm not sure on this but I think you have an externally regulated alternator. Are you changing to an internally regulated Alt.? If you are, then you need to do some re-wiring with the Volt. Reg. I converted a '72 Buick GS to an internally regulated but wanted to retain the factory look, so I added some jumper wires in the external regulator. The Amp gauge will be a problem if it's only rated for 40 Amps.
I used a "PowerMaster" 100 Amp chrome Alt.Check them out on the Web. Nice stuff!:bump2:
Thanks but it is internal. I ordered a 70 amp and might put it in and see what happens. The problem is, I cannot find an OEM replacement for higher amps and I would have to swith to a volt meter. Don't know what wiring changes that would bring. The other option is return the 70 amp and re-case my old one. Thing I don't like about the latter is I don't know what shape the old one is in.

Hey Buster, I put a chrome 100amp alternator in my 69-no rewire, no problem. Amp gauge works fine, no higher output than original. Chrome looks good!

Hey Buster, I put a chrome 100amp alternator in my 69-no rewire, no problem. Amp gauge works fine, no higher output than original. Chrome looks good!

OK, now you have me all excited! Is your amp gauge a 40 amp max reading?

Yep, Its a 40.

Yep, Its a 40.

Awesome, thanks! I hope to install that puppy tomorrow.

As info, installed and working great! No wiring changes and looks good. Still not finding a decent price on the upper alt bracket though!

good deal