Pistons WERE available in sizes up to .060" for the vintage Whizzers, however they are very rare and hard to find. Many companies are offering the new edition piston as a replacement and can be made to work.
The new edition piston isn't as tall from the wrist pin to the top of the piston, and therefore it doesn't end up level at the top of the stroke.
It is about .125" below the top of the cylinder, however it is the same in the new edition motors.
The biggest difference is in the wrist pin size, as the new edition pin has a smaller O.D. The vintage pin is 9/16", whereas the new edition is 14 MM, a diffeence of .0113188976377953". A few are supplying the new edition piston with a new rod bushing, however I found using an adjustable reamer and increasing the wrist pin holes in the piston to accept the vintage wrist pin is much easier, faster, and just better.
The short piston height can be modifed in several ways if necessary to make the piston even wth the top of the cylinder. One way is to use gasket sealer at the base and eliminate the base gasket, another is to remove some of the cylinder height by milling off part of the base.
The new edition pistons only come in .25, .50, .75, and 1.0. Don't assume it is in inches, as it is metric. The first O.S. is .25 of 1 MM or .0098" [approx .010" O.S.], second is .50 of 1 MM, or .19685 [approx .020" O.S.], third is .75 of 1 MM or .029527" [approx. .030"], and last is 1.0 of 1 MM or .39370078" [approx .040"].
One important issue to consider is the rings are much better on the new edition pistons, and the new edition pistons are currently available.
Check with Mike at Wizzer Works in Ohio, or Wildfire also in Ohio if you elect to use the new edition piston.
Have fun,
