Hi,
I'm the owner of a 1973 corvette C3 in Europe and I'm looking for speakers box plans.
It's not easy to get C3 parts in Europe and quite expensive to buy in the USA and ship them.
Does anyone have speakers box plans so I could built the boxes myself.

​​​​​​​Thanks

Speakers box

 

I would like to know as well

 

me too

 

I did build my own speaker boxes for my 1973., I don't have any blueprints, but it was fairly easy to design. I have a pair of Infinity 3-way 6x9s that I wanted to use. I initially used cardboard and laid out the speaker footprint on it, then took measurements of the height above the wheelwell in several places with a tape measure, trying to keep it as close to perfectly vertical as possible. Then measured it for a possible length.
I laid those measurements out on the cardboard and cut out a rough shape, making sure to stay well outside the speaker cutout. I had to test fit and trim several times to get what seemed to be a good fit, then transferred the cardboard design to 1/8" plywood. I needed to trim it further because the cardboard would bend more than the plywood. This piece fits tight to the top of the body arch above the wheelwell and extends back to the rear bulkhead. The speakers were so deep that I ended up having to raise the plywood up an 1.5" to clear the wheelwell.
I used the same method to fit another piece to the front of that one to keep from seeing the backside of the speaker. The only downside side from this design is that the speakers face toward each other and don't angle forward like the picture you posted, but I have Infiniti component speakers up front, so the rear only add some presence and mid-bass. Also, the bass isn't super deep or tight from the 6x9,s because the enclosure is not airtight. Though I do have the 10" subwoofer for that. Overall I'm very happy with the sound of the system, though I don't turn it up too loud most of the time, because who wants to completely drown out the sound of the engine!
I'll post some photos from my phone in a few minutes. Hope this helps some.

 

 

Ok, this might not be what you want to do, and they are not perfect. I cant see them with the roof down or the roof up for that matter so it depends on your need.

I made them from 1/8" plywood that I had laying around, some 1x2s, drywall screws, caulk, an old pillow, carpet cover from fleabay https://www.ebay.com/itm/256019876853?var=555957623363 , and spray on adhesive, flex seal spray, Kicker 6x9's from Crutchfield. https://www.crutchfield.com/p_20646C...46CSC6934.html
The long side is 8.5" x 12. The short sides are 8.5x8.5. 1x2s used to on the triangle sides to screw the sides to. Seams are caulked. Insides shot with a coat of flex seal. Pillow used as poly fill packed pretty snug. Installed the speakers and drilled a hole for wire. They are currently gravity mounted because the interior is on the list of things to do.