I have 3.73s currently, would I gain much SOTP feel from going to 4.10s? Also, the tahoe is my daily driver, so what kind of mpg loss would I expect?

 

I did exactly that, went from 3.73's to 4.10's in my Avalanche. The SOTP difference off the line is immense. There was already good power for me because of the cam and blower, but now there is serious G-Force pull with the 4.10's. If you want a race truck, the 4.10's are definitely for you.

The tradeoffs for me, however, have outweighed the gains, because of my driving habits, and because I care about gas mileage. Yes, the truck takes off great, but how often do I need that, compared to how I usually drive? Very little it turns out, because I do most of my driving on the freeway.

I've done some more accurate measuring lately, and the tradeoffs are exactly this:

- Lost 2 mpg with cruise control on, on flat road (19 -> 17)
- Lost 3 mpg on the freeway with no cruise on, and/or hills (17 -> 14)
- Lost about 1.5 mpg in town (14.5 -> 13)
- RPM's are higher at speed, more noise in the cabin
- Run out of gear sooner, earlier shifting

Hope this helps.

 

What tuning do you have(who) since you did the 6.0 swap? How much knock retard are you getting?

 

The 4.10 should put you right near where you were stock. Your fuel mileage will be worse just because of the tires, etc. Most GM gear changes are about 10% apart (3.08,3.42,3.73,4.10,4.56) so even though it sounds like a small gain it can be noticeable, especially in a heavy vehicle that needs it.

 

I have a Nelson Tune. I think it is great. I'm not sure aout the knocking retards though.
(JK)

My gas milage is *** right now (13.5 downhill with a backwind). So, fuel mileage really doesn't affect my decision. I killed that a long time ago. Thats why I bought a crotch rocket. My way of saving the planet. Go green.