Hard Accelerator Pedal?

[SourTooth307]

Ever since I bought my truck I've known it to have a much harder accelerator pedal than I'm used to. I had heard that it was normal before but a couple people who are pretty knowledgeable on auto mechanics have said to me that it's not right, one even went as far as to say that it seems like someone might have modified it to be harder to press. Can anyone confirm for me if this is true and if it is, what can I do to correct the problem? I'm guessing throttle springs?

My current set up is a 350cid with an Edelbrock 4 barrel, sitting lifted on the intake.