las tnight on woodward my 347 fox w/c4 started getting noisy and i thought maybe the exhaust was a little loose or getting that way,then the noise got really loud,more like a rattle.i thoght iw was my mac prochamber but ther's nothing inside the chamber to break loose and cause rattle.not wanting to ruin anything i had it towed home and there's no noise today when i had it up on jack stands and went thru 1,2,3.myguess is torque converter and its a performance automatic 10 inch with 3500 stall.any ideas as to something different?