Test your guage,Using an hand held temp. sensor read the water temp. at the rad intake, and out takes, and the block,
I have tested them and found there close to 160 at the themostate. hotter at intake and cooler at out takes.
I have a few used rads, but have thought of getting a quote on making new Alu. ones, But am sure they would be expensive cause of low number to be custom made and odd shape,.