67-68 Camaro Rear Bumper Width.

[38HAULR]

I am wondering if anyone has a 67-68 Camaro rear bumper that can give me a measurement?.
What I am after is the inside measurement from side to side. taken from the upper and lower edges of the wrap around .
My intent is a slight custom job on a 62 Buick Special/Skylark with a mangled rear bumper.
Specs regarding width of both vehicles tell me that the Camaro is some 2 inches wider, but I do not know where the measurement is done.
The Camaro looks to have the same shape rear bumper.

Thanks.
Frank.