2.5" to 3" Exhaust not sealing?

[Devil Man]

i had a custom 2.25 (i think hot shot is) to 3" flex pipe test pipe made to make this work cause to have a test pipe in and not have any flex pipe is stupid imo and puts alot of stress on the headers... just order a 3" or 2.5' flex pipe and get a local exhaust shop to make a adapter and all that shit to get it to bolt onto where the test pipe would be

here it is