We can't. Unless you scored some absolutely amazing deals on new or used, $340 is not going to get you a bonafide 60 MPH nitro touring car.
Let me ask this; have you ever driven a legitimate 60 MPH kit? Because a 1/10 car at 60 MPH is really moving. I've found with radar that people's perception of speed in 1/10 RC tends to be at least 50% higher than actual, meaning that a great many will swear a 40 MPH car is doing 60+. It's deceiving. And all those ads from Traxxas and other companies claiming overly optimistic top speeds don't help with that perception. The advertised "65+ MPH" Jato 3.3 is a 38 MPH truck in stock form at my elevation.
Be less concerned with top speed and more about performance at high speed. Trust me, top speed runs get boring, and a car that is only good for that becomes equally boring. I built an extremely fast RC10GT last summer, and it was fun briefly, but now that truck that we had clocked at 88 MPH before even putting in the Novarossi engine sits on a shelf, having donated the Nova and its receiver to a 1/8 scale truggy I will actually use.
A 50 MPH car that handles is a lot more fun than a 100 MPH car that doesn't.