RPM's during shifts.. plateau at 1800 always? Kind of weak feeling.

[300Drestoration]

So i've got a restoration thread going for my 1985 300D but i am hoping to hear some thoughts on one specific performance issue i may have...

Shouldn't the RPM's dip a good bit during all upshifts? Regardless of how hard or soft shifting may be set?

If i am at a stop light and ahead of me is a moderate incline and i accelerate around 50% throttle, once i arrive at about 1800 RPM's it will shift to 2nd and then eventually to 3rd and then finally to 4th. The spacing of shifts seems ok. But throughout all of this, the RPM needle just stays about 1800 the entire time, including during the actual upshifts. I would expect the RPM's to drop momentarily then gradually increase until following shift...and also would expect the sound of the engine to correlate to these RPM changes.

As of now i'm just getting a plateau of RPM's, both on the meter and also in the sound of the engine, throughout all of it and it's all at about 1800. Once i'm cruising upwards into higher speeds then i will gradually go into high rev's and all will seem good. But between the time i'm hit second and the time i hit 4th, it's just a constant 1800 RPM and the engine seems weak during this when going uphill.

The power/torque that i have in the lower speeds definitely leaves me wanting more. There are other factors to work on still, such as valve adjustment.

Any ideas?