I have just finished having a new engine installed into my 69 vert. It is a fairly robust LT1 stroker. Dyno'd at 550 lb/ft of torque at the rear wheel. The TH350 was replaced with a stock (not built) 4L60E. The shop has told me that with that much torque I should be using 3 as my vigorous launch gear rather than 4 (OD). They told me that the clutches are stronger in 3 than they are in 4. I am pretty much an automobile knucklehead so can anyone explain this to me in simple terms and does this sound reasonable? How long can I expect this tranny to last?

thanks

bob spears :confused:

the same amount of clutches will engage at the same line pressure in any given gear no matter where the selector is.

Actually when you move the shifter from the OD position to the "3" position a pair of additional fricions are applied. These frictions do add some holding power under acceleration.

These frictions are called the "over run" frictions. They also provide engine braking in the "3" position on the shifter

Not sure myself. But I always just put my 700 in 1st when I'm launching, and just shift through the gears that way. If I'm driving around town and such, I leave it in 3rd until I get on the highway, when od is needed.