I have a set of 10:1 TRW forged pistons with standard bore size I could sell. They are used but good. These pistons give about 9.3:1 with a stock engine. They were discontinued quite a few years ago. I have another engine with them in it except 30 thou overbore and it was about 600 hp with turbocharger, no issues with the pistons.
well in the ideal world custom pistons set to sit at zero deck are preferred. Second best is milling the block. Lastly milling the heads will work but it’s not as ideal. Although with iron heads is less of a concern as their isn’t much of a quench area. It’s vital with the alum heads though, closed chamber gives a quench area.