The right one for your Toyota Tundra is the S-7 Hydrogen Kit, and I would suggest the FS2 HHO Chip bundle for your enhancement.
The S-7 Hydrogen Kit is more than enough for that size engine, however you are almost in the D-7 kit range. So, IF you are pulling heavy loads constantly, using it as a work truck you may want to consider the D-7 Hydrogen Kit.
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