Copy a project into a new template file?

[still.james]

can this be done and successfully?

i have some old projects i would like to import into my new template file and was hoping it was gonna be as easy as copy and paste (not tried yet)

[Dimitri Harvalias]

The usual procedure would be to open the old project (Revit may need to upgrade it) as well as your template file, or a blank file based on th etemplate.
With both files open, from the menus in the old project FILE > TRANSFER PROJECT STANDARDS and choose which aspects of the template file you want to impose on the old project.