It's a GM spring, that's cheap and readily available at dealerships from what I've heard on the street.
Another low cost choice is looking to ebay for LS6 springs. Usually there is a set or two going very cheap. Only thing there is you shouldn't use them on a 96 or 97 head because of the shape.
cool thaks bill! do the LS6 springs have a diff max lift rate?
Going back to stock *GRANT built trans BLOWN w/17k*