Hmm, hot rod 340, little radiator, tight engine compartment, yeah it's gonna run a bit warmer than stock but 210 is not a problem.

Now if it starts puking coolant then yes you got an issue. Also, where are you getting the 210 reading from and how? Cause a stock guage doesn't give that.

They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.