[roger1]

In all the older cars I've had, I've always noticed a drop in air flow when I've accidentally killed the engine with the blower on high. Of course that's a pretty major percentage drop in voltage going from about 14.5V to about 12.6 at the battery. Accounting for voltage drop to the fan motor, the percentage is going to be worse. I'd estimate it goes down from 13V running to 11V when the engine dies. About a 15% difference.

I think you accomplished what you set out to do with your bench test. The new motor doesn't have the night and day difference that some have described. It stresses the point that it's important to not have leaks anywhere and that everything with the venting controls are operating just as they should.