Wide Open

Going from 3.42's to 3.73's your RPM's will jump about 150 at 60 MPH. 4.10's will cause about 300 RPM increase by comparison.
Acceleration differences between 3.42 and 3.73's will be minimal while going from 3.42's to 4.10's will be more noticeable. In my experience the mileage difference between the 3.73's and 4.10's was negligible though I noticed the engine was quieter and felt a bit more relaxed with the 3.73's. With the stock tuning and 4.10's my transmission would only downshift to 3rd at 60+ MPH while with 3.73's it would downshift to 2nd and pull harder. Just something to think about.
Once out of first gear I couldn't really tell the differences between the two gear sets.

lowreese

Thanks for your help.
I think I will go with the 4.10's.
I want the acceleration off the line, especially with these 24's (for now).
I still need some help with a stall if I should even put any in.
And trans cooler, any suggestions?

Wide Open

I don't see any mention of a cam that would necessitate a stall. I would suggest swapping in the 4.10's first and then deciding on whether or not to do a stall after you have some driving impressions with the new gears. The 350's are great motors and can make good power but they don't have the lungs the LS engines do and for that reason I would try the gears first. You don't want to get out of your power and too quickly with steep gears and a loose converter.
If you decide to do the stall the folks to the right can hook you up ---->
As for the trans cooler...most people seem to really like the Tru Cool 40K unit. I personally used two of the B&M Super Coolers because I didn't know of the Tru Cool when I was doing my build. My temps never approach 200.

lowreese

Thanks a lot man.
That sounds like the plan I am going to run with.
Appreciate the advice.

lowreese

What is the part number for the 40k in a 4l60?
Been trying to look it up, but can't find it.

lowreese

Anybody??

Chevy-Fun

iTrader: (1)

search google tru cool 40k it works with any trans its just getting the lines hooked an and mounting.

THE Tru-Cool 40K GVW Transmission Cooler Install Thread