Mike, I have several Excel calculators that I would like to post. Excel would not be required, since Open Office will work with Excel files and it's free. My question concerns the link to the file for download, is there a way for the file to reside on your server ??? If I post a link to my Dropbox account and something goes wrong on my end the link would be dead and the post would be useless. Here's a pic of my DCR calculator that will do 5 engines side-by-side. It also includes a Intake Valve Closing angle calculator, since this is a required number to DCR.