Originally Posted by elsangre
test 2
40mph = 2200rpm and 15 vac
44mph = 2300rpm and 15 vac
50mph = 2400rpm and 14 vac
53mph = 2600rpm and 13 vac

By my math, these RPM / MPH numbers are close to where they are supposed to be for 3.90 gears, certainly within the margin of error for tire size variance and torque converter slip.

Here are the numbers for 3.90 gears.

Road Speed vs RPM 3.90

Here are the numbers for 4.11's

Road Speed Vs RPM 4.11

As others have mentioned, ANY 350 in good working order should easily spin beyond the 3000 RPM mark. Sounds like you certainly have a problem of some sorts that is not in the tranny.