I have a ported box that i found in my shed but i dunno what cu. ft. is for it is there a way to determine it?

 

Measure it.

Do the math.

Or, you could fill it full of water, then dump it out and measure how much was inside.

 

http://www.the12volt.com/caraudio/boxcalcs.asp

 

Got it also is there any good box builders in the pittsburgh area? Or should i just buy an off the shelf box?

 

Lots of questions, but hopefully that will help you make good decisions. Do a google search with keywords - pittsburgh stereo custom - and see what you get(or similar). Call the place and ask them. Shouldn't be over $100 for a sealed carpeted box, be careful as they may try and sell you a pre-made box that is not the right cu ft..

 

Its not hard to measure the the enclosure. What kind of sub do you plan on using. I doubt a new sub is going to fit it. Ported enclosure are like buy shoes for girls. Everyone needs a diffrent size.