I will be darn... didn't have this issue installing the MTP-93 in my previous 91 :-( As you know it the MTP-93 is a larger batterie and it needs the second hole for the mounting clamp...
Well my 97 does not have threads in the second mounting hole so I gotta come up with some elegant solution here... Either use a metal taping screw or try to stick a nut under the base plate and use the original clamp to tie it down.. What did you guys did in this situation?
In the attached picture you can see the second hole I am talking about... How in the hell am I going to get the clamp in there :-)
I will hate to downgrade to the MTP-91's just for this :-(

http://members.roadfly.com/p.devita/Interstate%20MTP-91.jpg

Ethan,
You should be able to go to the hardware store and get what is known as a wellnut. They have a threaded insert, and a rubber outer jacket. You basically install the wellnut into the hole and start threading the bolt into it. As you tighten the bolt, the wellnut starts to compress itself into the hole and you should have a good mounting.

Thanks much Steff... Call me looser but I went with the MTP-91's ... I could not find a suitable damn wellnut in a 20 miles radius and I got really irritated and lazy. I will be better prepared for the MTP-93 next time maybe two years from now...

Ethan,
You should be able to go to the hardware store and get what is known as a wellnut. They have a threaded insert, and a rubber outer jacket. You basically install the wellnut into the hole and start threading the bolt into it. As you tighten the bolt, the wellnut starts to compress itself into the hole and you should have a good mounting.

I saw a box full of them today - should have said something