Strange Noises

Recently purchased an '82SC Targa. I'm hoping some of you experts can help me diagnose 2 different noises.
#1. A high pitched whine while in 5th gear that I at first thought was radio interference. Only hear it in 5th and only if depressing accelerator. If I just slightly depress acc. it doesn't happen. But push pedal down too far it starts up. Any thoughts as to what is causing it?
#2. A low pitched hum coming from rear only during left hand turn with speed over 45mph.
Neither noise is real loud but can certainly be heard. I would like to remedy problems before they get too bad or leave me stranded. TIA

possibly your 5th gear set is worn enough to cause a whine. it's the highest out of the oil and the 1st to go when the oil level gets down. if the R+P or pinion bearing was bad, you would hear it in other gears too. the rear noise on corners is likely a right rear wheel bearing.