Mine is 11X10X0.75 inch stacked plate, between the condensor and radiator.

You say yours does not lock up till 160F, and you get a reading of 215F when driving in 70F weather

Mine shifts funny when colder than 130F, and in 70F weather I get temp readings of 180F tops in 70 degree weather (as in after a hard run)

I think the 30F difference can be attributed to you having your temp pickup before the cooler, and I have mine after the cooler.

Perhaps?