‘73 Dart Sport Rear End Upgrade

8 1/4 rear in my dart sport 360. Drove for a good while with 2.45's! They sucked but had no choice. Funds were tight. Then slowly as funding permitted. Found some 3.91's on ebay for like $150 new US gear brand. Then an auburn suregrip from a member on here also new in box. And the difference was night and day!! Car is much more alive. Revs higher but moves quicker.:steering:also have heard that the 8 1/4 can handle @ least 500 horsepower. Not sure though.