common blocks and allocatable arrays

Hello!

I need to work on an old fortran code. The code contains a lot of subroutines and common blocks in each subroutine. I want to increase the size of the arrays defined in the common blocks in the subroutines. But the size for the static arrays is limited. So I start to consider the allocatable arrays. However, the allocatable arrays are not allowed in the common blocks. I am wondering if anyone has any good idea for this problem.

Thanks for your answer and help.