Over heat
3 Things
1. I have a friend who years ago had a 305 in a camaro, and it would only heat up at highway speed. Turned out the head gasket was partically blown. It did not use anti freeze either..... A pressure test usually will show this.
2. I have a corvette (93) at 70-80 mph on 90+ degree days the temp would keep creeping up. Now its a automatic with a 4.09 gear, so I was around 3000 rpms. Anyways, it was the radiator. They get old and get a buildup inside of them. Only thing that helps is replacement. I know you said you replaced the radiator, but was it with a new one?
3. Could be your gauge or sending unit. If it was mine, I would try a different guage ie aftermarket on it, if all else has failed.
3 Things
1. I have a friend who years ago had a 305 in a camaro, and it would only heat up at highway speed. Turned out the head gasket was partically blown. It did not use anti freeze either..... A pressure test usually will show this.
2. I have a corvette (93) at 70-80 mph on 90+ degree days the temp would keep creeping up. Now its a automatic with a 4.09 gear, so I was around 3000 rpms. Anyways, it was the radiator. They get old and get a buildup inside of them. Only thing that helps is replacement. I know you said you replaced the radiator, but was it with a new one?
3. Could be your gauge or sending unit. If it was mine, I would try a different guage ie aftermarket on it, if all else has failed.







