I have used Fortran for developing Computational Fluid Dynamics codes since 7 years ago. I have developed codes for numerical solution of Compressible and Incompressible Flows. However, I haven't worked on Spectral Methods. Therefore, you need to give me more information (including some references). Thereafter, I can give you a more precise and accurate information about the estimated time I need to complete this task.
This is a very challenging task, and, I am eager to cooperate with you on this project.