I have a dual t case set up with rf1a top shifts i believe both are. The intermediate shaft is the big 23 spline and the rear case has 4.7 gears. Looking to do a 5.3 vortec and im going to be rough on it what everyone opinion on keeping these or going with the 4l60e and 205 or even an sm465 with 205.... whats the thoughts? Just buy a $2500 atlas lol?