Intro to a port job

The cross over port, which would be cyl 4 or 5 exhaust port, is really fun to work with..
It either flows behind all the others at peak by 10 cfm...or if you pull the tape off the cross over side , flows better.
ATM its stuck at [email protected] w/pipe.
All the low numbers are within 4cfm less ,closest spread is 1 or 2 cfm in the .300-.400 then they make a really bitchin sound ...like blowing over a bottle with compressed air with the sound frequency breaking up @.450.. lol