What size blower was used to make the 575sc's? I have 525sc's with the 174 blower (or is it a 177?). What do you think it would do for power if I were to put the 575 blower on my 454's?

525 sc's have the 177. They work good for the 525 but cranking them up more can start making a lot of heat. Heat is your enemy. Going to a larger blower will allow more boost and less heat

525SC's are 454's with 177 SC's
575SCI's are 502's with 256 SC's.

If you were going to invest in new blowers I would suggest skipping the 256 size and going right into 671,420,871. The larger blowers allow more cfm, and you can spin them at less rpm/boost with little to no heat.