I have no experience with Atomic 4s, but I'm guessing that there are multiple holes on either the throttle lever at the engine or the pedestal, and that when you replaced the cable, you attached it to a hole closer in to the pivot of the arm. This would explain your limited travel now.
Check and see if there are holes further outboard from the pivot, and move the cable to the outboard hole.
You'll have to readjust it, but your throttle travel will increase.
1987 CS 36 Merlin "Kyrie"
"They drove a dump truck full of money up to my house. I'm not made of stone!" -Krusty the Clown