I would have to dig a little more to find the true factory rating on it. Most of those units put out 20-25 amps. Its not hard to get mixed up on generators as there were literally in the thousands of different Delco generator combinations. All having different armatures, fields, end plates, fan pulleys with different belt widths as well as pulley diameters and distance of the actual pulley from the end plate. Just glancing at my info I counted at least 17 different generators, just on chevy trucks from 1953-62, all built different in some way. Its dependend on the motor, with or without A/C, with or without Power Steering, optional factory amperage upgrades etc. I have all the original Delco Books from the early 30s up that give all the generator numbers, however, Chevy supplied most of their own pulleys, so the generator would be Delco and the pulley would be Chevy, this means you have to have some way of figuring out what chevy pulley was used. So if your looking for a 100% correct generator, you really have to know your generator parts, numbers, etc. or give someone like me a call that can tell you exactly what you need.
Fred, your dealing with a GMC, thats a whole different ball game than Chevy when it comes to starters and generators. Your 51 1 ton shows 2 generator numbers, Delco gen. #1102749 and 1102761. They both show to be the same generator so again, I would have to really dig to find out the difference between the two if any. I can tell you, both are the old style long straight case with the band around the brush end, 6 volt, aluminum end plates and probably a 5/8 belt pulley with an offset hub on the pulley as well. OK, Im done rattling on....
Ken
www.classicgenerator.com
