Hotter heater possible?

Is there any way to make my heater blow a bit hotter in my '70 Duster? I just replaced my T-stat with a 195* one and it didn't make a difference (probably because I noticed the T-stat I took out was also a 195* #-o). Will it ever be able to blow as hot as my family's '03 Town & Country, or will it always be a bit colder just by design?