1966 302 rebuild question about a piston?

What type of pistons? I've had some that were a little tighter than others. Make sure to oil them up good. Sometimes maufacturers aren't exact on tolerances. I'm assuming you have the press fit rods and the wrist pin is a little tight moving through the piston. If it gets tighter one way or another the wrist pin is irregular or if it's press fit and the rod is moving on the wrist pin don't install it! If you do it'll move into the cylinder bore and wipe it out. Hope this helps.:bigthumbsup