Joe,
When choosing a regulator it needs to be matched up with the generator. In your case if your using the original generator, Delco #1102793 it was built for a potential output of 45 amps. give or take. Most of the time they would put out well over that if allowed. This generator would have been used on 1st production 55s.
The 1118843 is a 6 volt regulator and rated for a max. output setting at 41-47 amps. The 1118827 is a 6 volt regulator and has the same amperage output setting of 41-47 amps. Basically the same regulator. If you went with a regulator of a lower rating your generator would still charge just not what its capacity would be. 25 amp regulator will only let your gen. charge max. 25 amps. This is why its important to match up your generator and regulator.
Just FYI, the second production 55s using any of the several 12 volt generators available had a drastic reduction in amperage output compared to the 6 volt generator. Even the optional power steering generator #1102041 was only good for 30-35 amps.
