twisteddually
+1y
Yes it will. I did the swap on mine last year. The 4L80E has an extra bolt in the top of the bellhousing, but other than that it is the same. I had to get different bolts for the torque converter, and the converter has 6 bolt but only 3 matched up on my flexplate, as it has 2 different 3-hole patterns. I also robbed some tranny cooler lines from the junk yard and spliced them into my lines, the 4L80E has 3/8 lines and the 400 had 5/16. I used the Compushift controller and it came with the throtle position sensor and all the wiring, I highly reccomend it, it's a very good product. Also you'll need to get a slip yolk and shroten the drive shaft.
In the end it ended up getting more expensive than I expected, but it was worth it to have that extra gear, and not to mention the shift control and other cool stuff.