Why is my 1991 corvette convertible overheating?

Holy hell, some people need to stay the F off of these boards...wtf is a "racing degree turbo"? Who the hell adds multiple alternators on a stock car? Holy hell... Hey Gort, before you answer, think before you type...my 89 GTA(almost the same motor as this guy's 91 'vette) can sit at idle all day long in 90* weather and not hit 210...and that's WITH an 8# procharger kit on it. Think before typing...especially if you're going to criticize someone...genius. Any properly cooled car can idle that long and not have an issue(unless of course it's a drag car). So yeah.... Like Buffman said....are you verifying it's really at 260*? The gauge or sending unit could be screwy. You also want to bleed/burp the cooling system, again...like Buffman said lol

have you verified it's actually getting this hot or just going by the gauge. Test the sending unit from the gauge if you're just guessing by that. Did you properly bleed all the air from the cooling system/

have you checked the oil?

this is just an educated guess. maybe the air intake flow isn't going in as smoothly and causing the engine to not have enough air making it to cause more force. or maybe the oil viscosity isn't the appropriate one making the engine shaft heat up. or maybe the antifreeze or coolant aren't 50/50 ratio or 70/30 in some cases . or the ECU needs to calibrated again due to modification to the car i.e. pro quality transmission, racing degree turbo, added alternators for more energy usage to electronic components.this are just some suggestions of what me a be a cause of the over heat