Slow truck
 

Hi - I'm new here and just off the bat will say I'm no mechanic nor very mechanically inclined. Having said that, I have inherited a 1989 F150 Lariat standard cab with the 305 V8 5 speed manual. It seems to run pretty well up to around 55 MPH, but above that speed it seems to run out of power. On the interstate on level roads I can get it up to around 65, but even a moderate incline will bleed off speed unless I run it at around 3k rpm in 4th. Is this normal? The truck seems very anemic in power for a V8. Also in 5th at interstate speeds there's a very loud whine that seems to be coming from the gearbox.

Any info is appreciated!