No, just custom is the only way to get a flat top for the 250. That's why the 307 piston is such a popular swap, its cheap and not expensive like a custom piston is.
Yeah, that's what I thought. It should still be an improvement in compression for the 307 flat top over the 250 dished, since both types of cast replacement pistons seem to be chamfered. It might be my only option when I decide to go the final step on my project and rebuild the short block and shoot for improved lower end durability and maximizing compression.
