Modern regulators are amazing creatures. Not only do they incorporate 3-step charging for the fastest charge possible, they also monitor the battery temperature to prevent thermal runaway. One of Balmars even monitors the temperature of your alternator to not overheat it.
However, the first step should be to ensure that your electrical system can handle the charge currents of a modern charging system. Are the wires big enough. Are the terminals clean, greased, and covered. Does your battery box have adequate ventilation? Also, you may want to consider installing a monitoring system first to see the before and after. We went for a Heart Link 20 so that we could separately monitor the two battery banks (starter, house) and see at a glance what their charge status is (nifty LED bar system with several colors).
I have been extremely happy with my Ample Power charging system consisting of a altternator on the Perkins diesel and a NextStep regulator. Finally it was no longer an exception to have full batteries. At idle, the house bank typically bulk charges at 50A, otherwise at 100A! Now that I have installed AGM batteries, having a powerful charging system is even better.
If you''re interested, have a look at <a href=http://www.vonwentzel.net/Prout/02.Electrical/04.Charge/index.html>that section of my web-site</a> where I show the installation. Lastly, Ample Power has a great website as well and professional customer service. Not only do you get to talk to humans, but they actually know the product, offer excellent advice, and when something breaks, they stand behind their reputation and send a replacement right away.