Will this work?

[SykotikCamber]

So I tried to design my own box (first time) using WinISD and SketchUp. I tuned it at 32 Hz with 2.75 cubes of volume. I wanted it to be 17 in wide and 17 in tall and so the box came out to be 27 and a half inches long. I also wanted the sub (Sundown EV3 12 D4) to be firing forward in the box. That being said, after drawing it out, I noticed the front portion where the sub would actually mount is rather short as you can see in the picture. So I have came up with a few solutions or  maybe a combination: 1) add a additional front plate that covers the front of the boards that are going the length of the box making the front section 1.5 in thick, 2)redesign the box with either a smaller port width or make it slightly wider (the box can technically be around 22 in wide i just wanted to keep the width down a bit to add a center console), 3) make the sub fire upwards, or finally 4) redesign the entire box with a smaller air space to make the speaker smaller. If it matters I am installing this in a 96 Dodge Dakota single cab. That being said, redesigning it would be appealing because after measuring it out, the subwoofer would be fairly close to the dash possibly making the sound quality drop. Anyways, any ideas on what would be the best course of action would be? Thanks ahead for any help I get. Also I guess I should add that I just joined the forum so welcome everyone. Don't be afraid to ask any other questions that I didn't answer. Like I said, I'm pretty new to this, so not 100% sure what I'm doing. I am looking to learn more about box building though because I enjoy it.

[SykotikCamber]

Oh btw I should add that the raised circle on the front represents the cutout diameter (inner circle) and outside diameter of the sub (outer circle).

Also another concern is the 3.75 inch gap between the inside of the wall and the end of the port. is that enough? according to WinISD I needed a 35.25" long port and thats where it ends.

[Triticum Agricolam]

Looks like you are off to a good start!  Nice job with SketchUp. 

I understand your concern about the panel where the sub mounts being pretty narrow.  I think you can fix that without a complete redesign though.  I'd make the side panel and the port panel each 3/4" shorter and the baffle panel where your sub mounts 1.5" wider.  This way the baffle overlaps the side and port panels instead of it being the other way around.  All your internal and external dimensions will remain the same.  The main thing you want to avoid is putting the mounting screws into the end grain of your panels, screws don't hold well like that. 

How much power are you going to be running?  2.75 cu ft is definitely on the big side for an E-12. 

How wide is your port?  The 3.75" gap between the port and the side wall is probably narrow enough it's going to lower your tuning some.  Regardless of that you will probably end up tuned a bit low anyway because WinISD doesn't calculate proper end correction for slot ports, FYI. 

[SykotikCamber]

First of, thanks for the compliment on SketchUp. That was my first time designing on SketchUp and it took me a few times lol. 

To answer your questions tho: 1) the port dimension is 2.75 X 15.5 inches 2) I'm running it on a hifonics brutus brx 1116.1D. Supposedly RMS power is 700 watts at 2 ohms however i have my doubts. That being said, knowing how sundown underrates their subs, and i doubt the amp is pushing much more than 500-600 watts, gain is turned all the way up and never heard any clipping or distortion. I still never turn volume all the way up just in case. Until I get it properly tuned first. 

Also you mentioned the box possibly being to big. I think sundown recommends either 1.5 or 1.75 (don't remember which). I was just going by the graph in WinISD though so if someone that knows more about it can give me better information, I have no problem redesigning. Besides it's fun for me anyways.

Anyways, thanks for the help.