I have a holley carb not sure of exact model bus it's a 4bbl. My brother set it up to be slower for me (so i dont kill myself) and my dad and i want to change it back for the weekend because we want to run it and see what it can do. The 4bbl now doesn't open up untill like 4500-5000rpm.....if i get a spring kit and make it so the 4bbl opens up right when i floor it will i feel a big difference or will it not make much of a difference??

 

Invest in a Quickchange Vacuum Secondary Housing Cover. That way you can change the springs easily and dial it in.

Holley lists it at http://holley.com/20-59.asp

Summit has it
http://store.summitracing.com/partde...p;autoview=sku

G