The block is paper thin though and easily holed. Once a rod snaps, it's all over, and the rods are weaker than the block. That being said, if deto is kept in check with either a cool enough air charge and good fueling and timing, or/and high octane fuel, stock rods and pistons can do around 300whp.

I don't know the differences with early model pistons vs new model pistons though. The V6s had weak ring lands in pre-2000 year models causing them to fail past 250whp or so, but that was all on pump fuel, don't know if they tried racing gas. But 2000+ models were good to around 270whp or so. All my zetec experience is with 2000+ year models and I don't know how the rings compare with the V6s.

2000 Rio Red I4 Cougar 200whp & 210wtq at 9psi 254whp & 276wtq with NX 35shot WRX TD04 Turbo, Cut Short Shifter, Strut Tower Bar, 17" ZN Wheels, Roush Springs, Starion Intercooler, NX 35 shot, HKS SS BOV, Full 3" exhaust,StreetFlight Chip