When we ran TZs, we changed the pistons & block once between practice & race during the TT, and still managed 105MPH a lap on a 350.

That was the only time we changed them.

Oh, and the ports were slightly *modified*, so yes, we did have chrome peeling off the barrels, but we still managed a complete season on two blocks.

These two strokes are tougher than they would have you think, as long as you can keep up with welding the cracks in the frame back together :?