My car was overheating badly, 220*F to 260*F on a constant basis, even while driving 45 - 70 MPH. I read and applied some great suggestions I got here to help fix this hellish situation even running a 383 with 305 stock cooling components. The dam really does make a damn big difference. When I bought the car the dam had been removed. They said they saw no need for it really and I have to admit that it does get annoying to hear it scrape on the ground (if you live where there is uneven terrain). But after I put it back on, the car didn't even reach 200*F.