416 running slower than expected

Need some more info....
1. Did you rejet it? It appears to come square jetted w/84's. Have you read the plugs yet? You may be restricting it a bit on the top end.
2. What size fuel line?
3. What GPH fuel pump?
4. At what RPM is all the timing in by?
Your initial timing for that cam is way too low. If you can shorten your centrifugal advance to about 10-14 degrees, that will help even though that will not affect much on the track, it helps.