I've been using the BA heads for over 10 years now in my 65. They work very well but do need work to flow. Currently my heads are being worked on...I will know the ### before long, but I can tell you they went into the "shop" flowing over 300 cfm. Now to the headers, a friend of mine, very good fab guy, and my self came up w/the idea to make adapter plates to get away from the poor bolt spacing on the exhaust flange. So I made plates to adapt to the Chevy "BowTie" header bolt configuration. This worked out "sick" My headers are steped from 1 7/8 - 2 -2 1/8" into a merge collector. It only takes me 15 to 20 minutes to take off the entire set...both sides! can't load the pix which may show what you need to see. pm me with your personal e mail and I'll sent the pix that way.