1973 electrical outlet box source

I need to find an outlet box that will fit inside the shallow AS wall, and allow a little room for a wire in and a wire out. The old ones look like they are about 3 x 3 5/8, and about 1 1/2" deep.



The single-gang shallow plastic ones at the box stores are ok for one wire in, but not enough room for a second wire, for when I run a circuit in a series. I don't want to use an external extension box, either.



I am using marine grade wire, and its kind of bulky



thanks

mike