I have posted two sets of pistons. 4.100 bore/4" stroke. In the engine mechanical portion of this web site. A quick info: Venolia, .200 dome, for stock rod length and pin dia. Gas ported and never hurt, just going a different direction. [stock deck height as well] $350.00 with old rings on the pistons, so you can see/measure the piston condition!
Piston set "B" is the same as above only flat top. same price.