Rear end gear ratio selection

[jimmythehand]

Going to be running the LSA connect and cruise package setup (LSA crate engine with the 4l85e transmission). If it matters, going to probably running 18in wheels. Going to be my daily driver. what do you think is the best rear end gear ratio to go with? thanks in advance.

[DavidBoren]

With a ~2.5 first gear, and .75 OD, you would do good with 4.10's.

[Schwartz Perf]

What size rear tire? The overall diameter of it is a factor.

-Dale

[gmorris]

With my 418 LS3 and 4l60 last year I found my 3.73's were a bit short for highway cruising and had me up over 2600RPM at 70mph. I swapped to 3.08's over the winter and the one drive I had with them seemed to work well....unfortunately the 4l60 then puked and I'm now dropping in a built 4l80. The slightly lower overdrive will favor the tall gears but the shorter 1st may not...although traction is an issue anyway so I'm not too concerned. My one drive with the '60 had me at right around 2K rpm at 70mph which is perfect for me. It really depends on your intended usage and willingness to out up with additional noise and fuel consumption if you go for shorter final drive. This is with a 25.4" tire (315/30/18).