I am running a 350 in my 55 2nd.it has the original radiator,and a good shroud.Engine runs just shy of 200 deg.Small blocks have a tendancy to run a little warm,as long as you keep it at 220 or under you should be just fine.Your 383 is nothing more than a stroked 350.I would however invest in a good heat gauge,and keep a close eye on it.

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