Mounting Battery Box - Need something like a drywall moly. Any Ideas? Quick Please!!!

[DSMRevolution]

I want to get my car running again before this Saturday, but I have one problem. I am relocating the battery and mounting the battery box in the right hand corner of the back hatch area (opposite of fuel pump - AWD). I do not want this battery to hit me in the back of the head in the event of a crash.

Try to picture this... I am mounting the battery box with a total of four bolts. I drilled two of the holes between the muffler and fuel tank. The bolts extend through the battery box with a large washer followed by through the sheet metal unibody area with another large washer and a nut underneith. The other two will go to the right of that. I can get nuts on the left side but not the right. There is no way for me to get to the underside of the unibody to put nuts on the bolt (that is without a huge 1 foot drill bit (do they make those?)). There is a brace unibody hump thing there in the way. I can't use self tap screws either because those will not hold to that metal and be able to withstand a crash.

Remember how sometimes you will put a moly in the drywall followed by a screw in it and the moly will expand and make it so it mounts the screw in the wall snug? Well I need something like that only for sheet metal. Do they make such a thing? If not, do you have any ideas? Either that or where can I get a 2 foot long drill bit?

I hope all of that made sence. I tried the best I could!

Thanks!!!!!

 

[sids]

mount it in the trunk, on the passenger side, there's a space there which is just right for a battery