I have a 375ish hp 350 .040 over 9.5c/r. I installed it after the first motor went bad. same hp out of a 327 11 c/r. It ran hot too but not like the new motor. The new motor over heats if it is above 40 degrees going down the highway. I put a measuring tape to the radiator. It is a 26W x 18T x 1in thick. The fins are actually 21inches wide. It is a Be Cool radiator. I have 2 electric fans pulling with no shroud. I just want to make sure before I build a shroud that I have enough radiator to start with.