[R-390] A vs non A

[Robert Newberry]

I may be picking up up what I believe to be a R390. When I was talking to a
friend about this he kinda scoffed saying they were less desirable and
harder to work on than the 390A.

Anything I should be looking out for on a 390?

Things that should be replaced right off?

Are parts harder to find on a 390 than they are on a 390A?

Should a 390 be avoided and continue looking for a 390A?