this web site will help you with all ur needs and questions about blow thru carbs..
I'm running 12lbs of boost in my 68 mustang, engine is far from stock. Dont forget that you will need a bigger fuel pump & boost referenced. This site can teach you how to convert a holley into a blow thru carb. It's a chore to get the engine tuned, but i did mine all by myself.. and let me tell u.. its a fun ride when ur in boost.
i've been running this setup for about 2 years and its been trouble free and low maintance. Very dependable after you work all the bugs out.