Pulling to the right when braking?

[CLASSIC87']

Hey guys I am a newbe to the site..... I have to say that this place Rocks!

My ride has been pulling to the right HARD... I replaced the both rotors & pads today. The thing is still pulling to the right, it's not a constant pull.. probably 50% of the time when I brake. Anyways the only thing I believe I have left is the calipers? I was wondering which one should I replace the left or the right.... my guess would be the right!?!? Or just do both...... ?

My tires and wheels are newer, I don't think this would be the problem either.

Thanks in advance for your input,
Anthony