I have a 1996 4.9 ford. Imagine you're looking at the temp. gauge... in about 1.5 miles from a cold start, my gauge gets over to the 'O' in the "NORMAL" on the gauge... that's about a quarter way up the gauge. My dad's truck, a '96 302, can go on the highway or in the city for hours and not get over the 'N'.

It used to go up to the "R", then I changed the thermostat. Now it heats up a lot quicker, but doesn't get to the "R" (It has what I described above). Is there something wrong with my truck?

Sounds like it is working correctly.

Yes, mine is the same way. Now my buddy has the same truck as us, and his will go all the way to the L and higher because of his thermostat.

its fine, anything below the red is pretty safe