crank length

I saw a bike at a garage sale and got it without much examination, at what seemed like a good price. Now that I'm having a closer look, I'm not so sure. This is a 15-speed Huffy Lakota. Everything works mechanically, except that the wheel can only barely turn to either side before the pedal...

I've installed this crankset on my Salsa and Fargo with 175mm cranks but they are too long. Can I buy just the 170mm cranks and spider from Sram without buying an entire new crankset?