My friend that owns local shop has another friend I know bringing in a 1991 350sdl I believe, he said he thinks OM603 engine, one owner, regularly serviced. If it doesn't have the 3.5L, should I jump on for 4k or so?

I also can buy my old 83 sd back for about the same money.

The 350 appeals to me, it's the turquoise and I need to verify the power to see if it's the bad one, anything else.

Thanks