340 tooooo hot

or so,until the rings seat,and everything is broken in.When an engine is new,there is more friction going on inside,creating more heat,a bigger radiator is not gonna change that.The good thing is,its winter time,i would go for a nice sundsy drive about 200 miles and back,preferably down the interstate,at 70 mph,then turn around,and drive 200 miles back,at 70 mph(at least 2000 rpms) you will probably notice the engine temp starts to drop on your way back on your little trip.Be sure your running a good synthetic oil,with a zinc additive,so the moving parts are well lubricated,and add a can of water wetter to the radiator to drop the temp some.My dad bought a nice 32 for coupe hot rod cheap 15 years ago for this very reason,the guy built the engine,and could only drive it a few mins at the time before it would go up to 225 degrees with a 160 thermostat installed.My dad is a long time mechanic,and new all about how to break in an engine,especially,a highly modified street strip type engine,so one cold winter sunday,the 2 of us decided it was time to break it in.We headed out towards the interstate,and proceeded to run 70-75 mph,from nc to south of the border in south carolina,back through nc,to va,and on the way back to nc,the engine temp dropped to 160.He has been driving this car for over 15 years,with the small hotrod radiator,huge cam,lots of compression,etc,and this thing runs cool as a cucomber,lol