NHRA rules for battery in trunk
 

I know the rules says I must have a sealed box if I want to have the battery in trunk. My question is if it can be custom fabricated. The boxes I've seen are just way too big for the battery I have, probably twice as big as I need it. Is it against the rules to have a custom fabricated one, does it have to be NHRA approved?

You can make your own custom box. They just have rules on the thickness of the metal you use. I believe they will make you put in a a cutoff switch that is accessible from outside the car also.You can find the rulebook online.

We have taken a thin holly, or optima style battery and laid it on its side
in the spare wheel well with and outside cutoff switch and then covered the entire opening with a removable plate and NHRA said ok.

Thanks guys. My spare tire well has a fuel cell in it so I guess that's not an option. I just read the rules on NHRA site and I guess I can make my own. They say I need at least 22ga steel. Doesn't have to be completly sealed. Just enough that it won't gush out if it does explode or crack.

Guess I'll be fabricating my own soon