Have a chance to buy a 1983 SD with 175,000 miles. Starts great but has blue smoke for awhile and and low rpms. Loss of power in lower range, but gets better in higher rpms, smoke lessens. Seems to miss a bit in lower rpms.

Michael,

Sounds like valve guide seals (at least).

If it's misfiring at low revs then performance will be down. Why it is misfiring could be almost anything.

Try to get a drive of another one to see if the lack of go at low revs is a fault with this articular car, or just a characteristic of the model.

If you go ahead with this, adjust your offer price to allow for some engine work. Wether the engine work is major or minor can't be established without some investigation that I guess the owner wouldn't want you doing

If the price isn't right to allow you to do some fixing, walk away, there's plenty more out there.............

__________________
Paul Gibbons
'93 320CE
'73 Jensen Interceptor (Resting)
Giant Full Sus Mountain Bike