restoring A7's

[whitebroncoii]

Have seen photo's here of others A7's and see that the ports have been modified, any info on this would be helpful.
bt

In 1988 I asked Jerry Hubbard (Altec engineer in OKC)
for the following port openings on the A7, A7-500;

8.25"H port when horn mounted on top
13.75"H port when horn mounted inside the cab