Fortran to C++ CFD re-write -- 2

I have source code for a bespoke CFD program, written in Fortran, that I would like to re-write, slightly restructure and update to C++. The FORTRAN code is structured: Main program: 570 lines 14 subroutine files Total Code Lines: 2487 but a lot of those are repeated COMMON blocks and comments. I have source code for a bespoke CFD program, written in Fortran, that I would like to re-write, slightly restructure and update to C++. The code has been in circulation since the mid '70's, and has been modified in 1990's and by myself over the past 3 years. I edited it to compile on GCC gfortran so I could package it into 64-bit exe and added some handy logging functions. We typically use this code internally, but we have also distributed copies of the binary .exe and manual to customers. I can provide further details, and if we enter into an agreement, we can provide the source code. I also have the original Manual/Documentation as well as a version that I recently wrote that we supply to customers. The FORTRAN code is structured: Main program: 570 lines 14 subroutine files Total Code Lines: 2487 but a lot of those are repeated COMMON blocks and comments. Some of the Code Restructure Ideas include: 1) When the code was originally written, all the input data was in the form of Punch Cards. In the 1990's revisions, the syntax and structure was maintained, but migrated to an ASCII input file. It has some weird formatting and all variables must be entered perfectly for it to work. I would like something that is more readable, easier to maintain and easier to implement extensions or refinements. For instance, I would like to use a few source files that the code can scan and interpret so that they're more free-form, with a 'run_control' file. The 'run_control' file would be the first file read and it would specify the other source files that could be copied (by the user or the program) into the run-directory from a central library. Additionally, since I mentioned that we provide this to customers, I would like to be able to #include these library files at compile-time so that we can control the access to information that the customer has. 2) The code is victim to silent errors that will cause it to crash, so implementing some error/warning flags would be useful. The main effort is for a windows based console application, with a possibility for a GUI to be wrapped around it at a later time. We are wondering what sort of effort this might be, and what you might be able to propose. How familiar with CFD, numerical modeling, FORTRAN 77, and the other aspects of this project are you? We are flexible on delivery time and budget. The below are estimates.