Every motor is different in deck height, gasket thickness, cam base circle and if the cylinder head has been decked just to name a few. It is best to get a set of adjustable pushrods, they are easy to use just check the geometery. I did it on my car it was pretty easy. If you don't want to do it right then TFS should have a pushrod lenght recommendation in their instructions.
You should be right around 6.7 or 6.75 in. with that cam, but Troy is correct about the variations you may come across. There's nothing difficult about using an adjustable pushrod. You draw a line in permanent marker across the valve stem, rotate the engine one revolution, and check the pattern on the valve. It literally takes 10 minutes tops to do. Where in IL are you from? I have one sitting in my toolbox that I could let you use if you're local.