speaker box question

i just got 2 12 inch SPEAKERS FOR MY 94 Z28 could anybody give me the dimentions for the box and any tips on building it

That depends on many factors..

are they subwoofers or just speakers?

What brand/model? Each model likes a different area inside.

they are 12 inch rocksford fosgate punch

P1, P2, P3, Punch Z, HX-2, HE, HE2?

They're all different?

punch z

RF recommends 1.25 cubic feet per driver for punch Z's.

19.75 x 12 x 14 is what they recommend for one driver. Just double the length if you wish to build a dual box, but be sure to put a divider in the middle, so they do not interfere with each other, and doesn't blow the other apart if one fails.

Measure twice, cut once. Always use a bead of liquid nails between the boards you wish to join, and drill pilot holes where you'll be using screws. You can use either sheetrock screws, wood screws, or my personal favorite, decking screws with the two different threads. Once that second thread hits the boards get joined exceptionally well.

Use a router or jigsaw to cut out the hole for the speaker and the terminal cup if you're using one. Leave the board where the speakers go in off for now. Once you've got everything joined (save for the top) put a bead of silicone along all the corners, insuring a tight seal. Dont forget the terminal cup. The stuff is potent, so use in a well ventilated area.

Another bead of liquid nails, pilot holes, and the top is on. If you can silicone this too, great.

Let it dry for a while, carpet, load and boom.