Tundra 8in re audio box help??

[Rockford96]

my dad wants some bass in his truck its a 4 door sr5 toyota tundra 5.7 but the sub is a re audio rex8d4

but i need help with the box my mad dimensions are 6in high 13 wide 13 depth its about .4 cubic foot in torres i came up with 6 high 13 wide 13 depth with 2 1in aeroports 7 in long for a tuning of 35 hz and 1.57 in squared of port area does this sound about right it will be under the back seat in the truck