He does all the popular transmissions.
If you have the 4l60E with the 6 bolt extension, not the 4 bolts, you will also need this adapter if you want to use the stock speedometer. Because GM changed the way the housing bolts to the extension/transfer-case you will be unable to retrofit to the earlier extension with the correct speedometer adapters.
Link for the 4L80 part;
https://www.ebay.com/itm/22357274653...Bk9SR8jf2OOmYQ