operating temp range for 70's 350???

[hoodup]

So my trucks temp gauge indicates that my water temp is around 225 to 240 deg witch i know is too hot...so i thought maybe my thermostat was stuck closed so i replaced with your standard 195 and im a little less but about the same as before!! could my gauge be not accurate and if so, if i shoot a laser temp gauge on the block what should it read to indicate the correct temp? HELP!!.....

PS I hope i put this thread in the right spot guys,,sorry if not