What excatly must be done to make a rear mounted battery NHRA cert.?

It has to be mounted in a NHRA certified battery box with a vent tube to the outside etc. and must have a kill switch easily visible clearly labled kill switch somewhere on the back. You can mount the kill switch behind the license plate and then remove the plate when you go to the track. There may be a few more specifics, but that's all I know at the moment.

That's pretty much it, just make sure the box you buy is NHRA approved. The ONLY plastic box allowed is the Moroso box.

Make sure your alt is wired through your switch also. When you go through tech, they will shut the switch off and it needs to kill the car. The only way to do that is to run the proper alt wire through your switch along with your positive cable.

Here's the offical statement from NHRA tech questions on their site.

FAQ's

I have a street car that I occasionally run at the strip. I've relocated the battery to the rear. What else do I need?
Any car with a relocated battery must be equipped with a master electrical cutoff, capable of stopping all electrical functions including ignition (must shut the engine off, as well as fuel pumps, etc.). The switch must be located on the rear of the vehicle, with the "off" position clearly marked. If the switch is of a "push / pull" type, then "push" must be the motion that shuts off the switch, and plastic or "keyed" typed switches are prohibited. Also, the battery must be completely sealed from the driver and/or driver compartment. This means a metal bulkhead must separate the trunk from the driver compartment, or the battery must be located in a sealed, metal box constructed of minimum .024 inch steel or .032 inch aluminum, or in an NHRA accepted plastic box. In cars with a conventional trunk, metal can simply be installed behind the rear seat and under the package tray to effectively seal the battery off from the driver. In a hatchback type vehicle the battery box is usually the easiest solution, since the alternative is to fabricate a bulkhead which seals to the hatch when closed. At present, Moroso is the only company which offers an NHRA accepted plastic battery box, part number 74050.

But I drive on the street. I don't want a big cut off switch hanging on the back.
This solution takes a little work, but it solves the problem. Install the master cutoff inside the vehicle, positioned "sideways" so that the toggle moves forward and back. Drill a hole in the toggle handle, and attach a steel rod that will run out the back of the car, through a hole drilled completely through one tail light assembly. Have a spare tail light assembly on hand, so when you come home from the drags, you remove the rod and put the cherry tail light back in for street cruising. Next time you plan on going to the drag strip, swap lights and reinstall the rod. Since the drilled light is for the strip only, you can also have it marked "PUSH OFF" in big letters so the Tech Inspectors will think you're cool.

yes that switch would work. I'm not a wiring guru so I couldn't tell u how to wire the Alt. I'm sure someone else will chime in on that.