Well since I see we pulled this one back out of the grave let me ask you. What would it cost aprox. to rebuild a 700r4 (that I got for free) to be able to handle 400+ horse and same for torque. I want to stay with an auto so it is either the 4l80E or the 700R4. Yes i know it is the tougher one of the two But since I either have to rebuild the 700R4 or buy a 4L80E I wonder how cost efficient it would be. By the way does anybody have information for a vacuum mod for the 4L80E.