I'm wanting to replace the original Delco-Remy external regulator type alternator with a more modern upgrade. The direct replacement is a 20SI series using the SAE J180 swing mount. Research also shows the 30SI, and the 33Si series to use this same mounting setup. This is a 24VDC system and I've not had any experience with anything like upgrading to internally regulated from externally regulated in the past on equipment. Which is the best alternative of the three listed choices? Not worried about the wiring at all; just don't know benefits, or detractors of the choices as seems any will physically fit.
Seems all the more modern "SI" series alternators are brushless nowadays. I have plenty of room to the rear of the alternator mounting area so most anything in the series will physically fit. Thinking of going with the 26SI series as it is the modern replacement for the 25SI series. It also is high enough in rated amperage, (75A@24VDC) to satisfy my requirements with LED lighting upgrades.