Oil consumption the THIRD

Could be desperate... for oil consumption and blue smoke...
In the meantime, I did the following:

1. Intake manifolds replaced;
2. Crankshaft ventilation hose (front)
restored in original condition (in old condition was restored
he was led outside... so the blue steam was loud
Previous owners a little better..)
3. Oil change with filter and 1 L "Mathy"
Good addition)
4. Set throttle potentiometer (click).
The part does not sit 100% plan; is that normal??
5. Old error memory deleted.
6. Compression test (see Appendix)

Since then, he's been running differently; I'm trying to describe:

a) A bit rough, as if (perhaps) not all cylinders to
Run 100% round?
b) One might think it is perhaps a wheel bearing, or
the tyres (245), or a drive shaft
c) but it could also trigger
be?
d) Somehow the power is missing in the lower speed range (he
==References== 4000U/min.)

Found out previous owners: former mechniker
He told me that he already had the same problem (oil consumption) and therefore:

a) the valve shaft seals have changed – without success!
b) With the tooth grate (at 195,000km) also
the water pump; and
(c) both distributors changed.

What else can I do - without disposing of the engine, or completely rebuild??
Greetings, Robert