Can I use a 78DT Battery?

[bobc455]

In my '04 GT, I would like to replace the group 34 battery with a group 78DT that I have.

Any reason that won't work?

-Bob C.
p.s. In anticipation of some questions....
1) My existing 34 is a 5-year battery, and it's 6 years old
2) I have a barely-ever-used 78DT from another car that got scrapped
3) It looks like the side terminals would be a convenient way to connect my amp

Flame suit on...