Hello!

I wanted to know where everyone is getting oversized RT3 pistons. Thanks!

You could try to reach out to member Enduronut, he had a pretty big supply of pistons and rings that he's been selling over the years... he pretty much always had a good selection for most models, probably less so as time passes. He doesn't post here anymore but he might see this and contact you or you could try to message him.

I would like to add my experience. On 2 of my RT3s the cylinder liner separated from the cylinder after they were bored out to the third and fourth oversize piston. The liner became too thin. This caused a small air leak and a lean condition. The shop that does the boring for me recommended not to go past the second oversize on the 360. The liner is 4mm thick when new as opposed to 5mm on the 250.

I have NOS cylinders available for sale.

Plus many of the pistons and rings I have came from Enduronut.