The best replacement for voltz is tekkit.

The best alternatives to voltz are rated as following:
★★★★★  tekkit
★★  ampz
★★  ftb
★  tekkit lite

Your alternative for voltz is not listed? Suggest!
Speaking about voltz, one probably shouldn't forget about bukkit.

Other search terms related to voltz and their ratings are:
★★★★★ bukkit
★★★ galacticraft
technic launcher
You have in mind a companion for voltz and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of voltz in all years. Click on graph for more.
voltz
tekkit
ampz