How would this setup be for a 50 Chevy?

I've got a rebuilt 350 SBC with a rebuilt TH350 tranny and have been looking for a rear end to put under it, hoping to find a 68-72 Nova or 67-69 Chevy with a 2.76 gear ratio so I cwouldn't be turning the motor at high rpms at speeds over 55. I found a rear from a 57 Chevy 4 door locally with a 3.55 rear for a pretty low price. The rear end will need bearings and all the brakes redone, but I think I could get the rear for 50-100$ I am running stock 15" wheel on the car. What type of rpms would I be spinning in the 65mph zone? Should I just wait and keep looking for a 2.76 Nova or Camaro rear end??

 

Try this.
http://www.mustang123.com/calculators/Top_Speed_Calculator.asp