For instance If you have a 4L60E car with a 3600 stall that has 400rwhp
what would a TH350 with a 3600 stall be producing to the rear wheels in the same car?

Anyone know the drivetrain loss percentage?

 

I wouldn't expect any significant difference, unless you have reprogrammed the 4L60E to lock up the converter under WOT. In that case, you would see ~5% more rwhp with the 4L60E. BTW, I never understood the 4L60-TH350 swap. A 4L60 can be made just as strong as a TH350 without giving up OD.

Rich

 

Drivetrain loss on a Dyno are Averages and for a Auto (whatever type) will be anywhere from 20/25%

 

The loss is primarily in the converter. If the converter is locked you wouldn't see any significant difference between an auto and a manual tranny. As far as differences between automatics, if the converter is taken out of the equation, any differences between trannies would be trivial. The parts in a TH400, for example, are larger and heavier than in a TH350. So, there is a small amount of additional hp loss when measured on an intertial dyno like a Dynojet due to the greater rotating mass of the heavier parts. But again, this would be a trivial difference. The TH350 and 4L60E are very comparable in terms of rotating mass, so any differences would be attributable to the converter.

Rich