......it depends on what type of blower your running & the amount of boost... I just had a 413 small block re-built and was considering going with a blower. With a 6:71 or 8:71 w/ dual 750 blower carbs, the required linkage & an upgraded fuel system I was looking at spending around $4,500 to $5,000.... I mentioned 'the amount of boost' as being an exspence cuz the more the boost the more heavy duty your parts need to be.... Check out the Holley web site r/e the Weiand Blower information page.... hope this helps, Bill