I have a 63 250hp/327(no A/C or power anything). I have my original alt. which I think I should replace. What is the correct amperage alt. for this car? They go from 37amp. to 100 amp. Would it be a good idea to convert this to a newer style alt. or stay with what I have and not have to mess w/ wiring?
lib, I own a '63 roadster as well and went through much of the same journey as you during the restoration process. As I recall, the original alternator was a mere 32 amps. I found out the hard way what happens if you put in a
100 amp. alternator, without rewiring - you fry the electrical, including the ammeter. If you check your ammeter, you will find that it maxes out at 40 amps, so that is the highest you should go with an alternator, if you want to keep your stock wiring. In my case, I went with a chrome single-wire Powermaster 100 amp unit (Model 27294) and ran a heavy 8 gage wire directly to the positive battery terminal. The reason for that was the alternator failed to "sense" the true battery voltage because of the circuitous nature of the original wiring and overcharged the battery, causing it to literally "boil" over. I also went to HEI and eliminated the external voltage regulator at the same time. I mounted an under-dash voltmeter, which I personally find more useful than the ammeter. Here's a link to the alternator I used:If you have not added accessories, like vintage air or a monster stereo, then the original alternator works just fine.
The stock configuration alternators went up to 62 amps, so that is as high as you can buy, however, there are still independent auto electric shops who will build you one up and above the 62 amp, if you really need it. That simplifies wiring changes.
I would NOT trade or throw away the original alternator, if it is really the original. You may not want to now, but you may want to restore the car some day and the alternator is another piece you'd have to buy and pay decent money on to make it correct.
BTW, you can have the original rebuilt to higher amperage and it will not affect judging if you go that way. Just be sure whoever builds your alternator doesn't sandblast the case to get that "new" shine to the aluminum. It will obliterate the stamping numbers on the case, making it worthless from an originality standpoint.
Your original alternator was part #1100628 at 37 amps; max used (for an a/c car) was 52 amps. As was noted, check the max ammeter calibration in your car.
lib, I responded to you last night, but my message isn't showing up on my browser, so I'll repeat my original response. My apologies if it shows up twice!
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lib, I own a '63 roadster as well and went through much of the same journey as you during the restoration process. As I recall, the original alternator was a mere 32 amps. I found out the hard way what happens if you put in a
100 amp. alternator, without rewiring - you fry the electrical, including the ammeter. If you check your ammeter, you will find that it maxes out at 40 amps, so that is the highest you should go with an alternator, if you want to keep your stock wiring. In my case, I went with a chrome single-wire Powermaster 100 amp unit (Model 27294) and ran a heavy 8 gage wire directly to the positive battery terminal. The reason for that was the alternator failed to "sense" the true battery voltage because of the circuitous nature of the original wiring and overcharged the battery, causing it to literally "boil" over. I also went to HEI and eliminated the external voltage regulator at the same time. I mounted an under-dash voltmeter, which I personally find more useful than the ammeter. Here's a link to the alternator I used:
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