I took a look at my Revell of Germany M60A3 (basically the same kit as your Blazer). The hull is fine on mine. Are you talking about the way the road wheel mounting arms are slightly offset from right side to left side?
If so, the actual tank is like that because the suspension system uses torsion bars that go through the entire hull. One bar comes in from the right, the other from the left so the road wheel arm mounts are offset with the left side mounts slight forward of the right side mounts.
This is a common feature on US armored vehicles since the M18 Hellcat, M24 Chaffee, M26 Pershing going all the way to the M2A3 Bradley and M1A2SEP Abrams.