I'm just not really a fan of Ross pistons. My boss had issues with some in a turbo buick setup. He ended up with over .009" clearance and they were still trying to stick in the bores. They were getting sponsored though so in went the JE pistons and the Ross sticker stayed on the car.
I also built a 4 valve mod motor ford. Stock stroke, new rods and ross pistons. Piston skirts hit the counterweights. Stock crank??? How did they miss that?
Course everyone seems to have issues now and then.