Upgrading sound system

[blown motor]

Background: I bought my 74 Challenger in 2012 and it had a Clarion radio and Clarion speakers in the kick panels. These were 80s vintage. I wanted better sound without breaking the bank and putting in an amp and big speakers in the trunk.
I opted for a radio from Antique Automobile Radio because I wanted the original look. http://www.radiosforoldcars.com/ Then I bought Focal ISC 130 speakers for the kick panels. http://www.focal.com/en/car-audio/car-audio-kits-solutions/integration/universal/coaxial-kits/isc-130 To complete the package I put in a Custom Autosound 4 x 10 dual voice cone speaker in the centre of the dash. (Pic 1 & 2) http://www.casmfg.com/DVC_Speakers.htm

Aftermarket products that are supposed to be drop in aren't always so, which is why I'm posting this. Hopefully it will help someone else.

The dash frame has a hole in it that allows room for the speaker magnet. (Pic 3) However these new speakers have a much bigger magnet than the original ones and they don't drop in. I had to cut a piece out of the frame to allow for this. (Pic 4) I used a Dremel tool with a cutoff blade to do this. That is the only thing I had that was small enough to get in there. So I got the speaker down into place (Pic 5) but it was too high to get the speaker grill installed properly. I had replaced the dash pad three years ago and the replacement had foam and vinyl top covering the speaker opening, unlike the original which was bare steel in this area. I cut the vinyl and removed it and the foam to get down to the steel core. (Pic 6). It didn't gain me a lot but it was some and it helped but still not enough. Next I trimmed the ribbing on the back side of the speaker grill to allow it to sit lower as it was hitting on the speaker. I used the Dremel with a grinding stone.  (Pic 7 & 8 )  It took a lot of time and patience to get it just right but I got it and it looks great. (Pic 9)

Along with doing this I took the gauge cluster out to send away for a refreshing. Since I have a bunch of loose wires in the dash I don't want to put power to anything so I haven't tried the radio to see what the sound is like. I'll update this thread on that later.

[Cuda Cody]

That was a tight fit!  The speaker grille looks great.  Update us on the sound when you get it working!   

[303 Mopar]

Did you look at installing 2 mini speakers as an option?  I've heard of guys making this work.

[blown motor]

I have heard of that option. Not sure why I went this way instead. Just did. I guess it just seamed a little simpler.

[Brads70]

I had to trim my dash frame too.  To be honest I rarely turn it on... I prefer the music the engine makes!

[blown motor]

When I got my car five years ago the engine music was all I needed. Now I find myself wanting some tunes sometimes.

[cataclysm80]

Looks good, nice to have pictures that show what's going on.

Regarding the single 4x10 vs two small round speakers...
the 4x10 being a larger speaker will be better at reproducing lower notes.  The single 4x10 should sound good, and it would outperform a single small round speaker.
Two small round speakers won't be as good at reproducing low notes, but they will be louder because you can hook up both front channels.  By giving up a little sound quality, you get a lot more volume.

Either way is fine, and I'm sure you'll be happy.
If you notice a volume difference front to rear, just use your fader control to put a little more sound up front.