I just purchased an '87 coupe. Previous owner used conventional motor oil and I would like to switch to Mobil 1. Is it OK to make the switch? Thanks.

Yes it is okay, I think Mobil one is recommended in That year aswell

I have added it in a number of used 350 pick ups in the 75 to 80,000 mile range with out any problems.

yep, engine sould like it :iceslolan