[mongocanfly]

i would just look for a 5.3/4l60 combo pullout..look for the earlier yr models..then youll have everything you need.. if you go with dbc itll be a little cheaper...if you get dbw be sure you get all the accelerator parts with the engine....the LS has already proven itself to be dependable in stock form .....no real need for a 6l80...the final od gear in a 60 and 80 (4th&6th )is practically the same...but I would not go any higher than a 3.73 gear and that depends a lot on your tire size as well..if you have a 3.54 rear it may be ok ...there again,depends on your tire size..im running 4.10s in one and 4.56s in the other with a od trans.....as stated above you can get the rpm to low with a high gear

4l60
1-3.059 2-1.625 3-1.000 4- 0.696 r-2.29


6l80
1-4.027 2-2.364 3-1.532 4-1.152 5-0.852 6-0.667 r-3.064