And that is correct.
XP-60 was last in line of Curtiss' attempts to succeed their immensely successful Hawk/Warhawk series. The XP-60 variants were equipped with several different engine configurations, XP-60C being the one with P&W R-2800-53 radial engine with contra-rotating propellers, although originally it was planned to use massive, 2500 horsepower Chrysler XIV-2220 engine that was in development at that time. Other variants used different R-2800 variant with four-bladed propeller, and Allison V-1710-75 liquid cooled engine with different superchargers.
In the end, after several years of development, the XP-60 did not offer any advantage over existing US fighters, and development was stopped.
Your turn.
Edit: sorry, can't rep you yet.