No, I thought the same thing. In fact I was in the process of sending my Denny's ds back to them when I measured the trannys..they are almost the same. Remember you have to swap front yokes too.

 

im not laying down a few grand on a 4l80e i was able to get a steal at work but i didnt know if its worth it or not, 4l60e thats in my truck is on its way out, so ill prolly put a stall in the 80e and go with it, thanks everybody i appreciate all the help its been nice