gear ratio ?

[K5owner]

Owning these trucks and upgrading them never makes you any money, you drive and own them because you love them. I swapped a 700r4 into my CUCV and took out the TH400 and it cost me little. Now if I had dropped in a 4L80E then yes i could see you spending a decent amount in doing so as the controller for those trans are pricey. The entire swap including finding the correct converter and trans was just over $700 bucks after I sold off the 400 and converter. Well worth it as the 6.2 went from 16-18 MPG at 55-60MPH screaming down the fwy and out of my powerband to 18-22 MPG while at 65-70MPH in the correct powerband and at a normal highway speed that wasn't going to get me run over on the freeway. It is all personal choice. On as heavy and big as a burb is riding on 35's and with a SBC I would stick with the 700r4, 4.56's (for reg driving) to 4.88's(for towing) and enjoy what that package can give you. Better yet would be a 6.0 with a 4L80E swap out of a newer GMC or chevy and then use some 4.56's.