That's going to depend largely on the cam's lift and timing. If PtV clearance is too tight, pistons made specifically for TW heads with 2.02" valves will still need to have valve reliefs cut. The reliefs that they currently have will most likely be too small for a 2.100" valve. If memory serves, valve reliefs are cut either .030" total or .030" per side larger than the intended valve. This means that if they're designed for a 2.02" valve they're, at most, 2.080" in diameter. Running them as is with the heads you're asking about runs the risk of the pistons hitting the valves.