Chevy 383. 30 over bore roller CAM Dart heads msd. Ign

Check the radiator for cold spots if you feel any the rad is no good. With two fans it should not overheat.

One other thing, I didn't read what you had in it thought it was stock lol. The bores n a 350 are not that thick and if you are running compression over 10:1 you can expect this the only thing would be to try to make rad larger. Maybe put in a corvette water pump but I also assume you have a an electric water pump in it as well.

How high is the compression? If it's higher like I said will cause it to overheat or run hot also they have an additive sold at all auto parts stores to put to coolant to lower the tem p which works very well. You should also be running coolant as it will run cooler with coolant than water. You might check to see if water pumps are listed different, like a/c to non a/c an dget the a/c style pump. Sometimes the vanes are different in those. Btw the bore thickness in a 350 isn't that thick either.