After install you will always want to Sync The App With The Motor.

Always use a timing light - Here's a couple of suggestions.
1) Set a program in your app to 12* across all rpm points. Start the motor and verify that you have 12* at the crank. If you do not simply loosen the distributor and turn it until you do. Once you have 12* at the crank, tighten the distributor down. The app is now synchronized with the motor and you can now confidently add a program of your choice and know that it is accurate.
or 
2) Pick any point along the curve and verify with a timing light that the point on the app (both the rpm and degree) is the same at the crank. If not loosen the distributor and turn it until you do. Then tighten the distributor down.