Dude, I'm pretty sure PLENTY of people have told you what is needed for a 3.1"...I know I have...I have a built low compression motor with a huge cam and ported heads...and I am running a 3.1"...with more room to play, sure...but a 3.1" isn't for you...MAYBE a 3.6...MAYBE. But I doubt it...you NEED stock size...or mods...like headers and a tune for one. But read my damn thread first guy.