These Are the Best Deal for Aluminum Heads Going... they Flow as well as AFR's Unported, and are Inexpensive... 195 CC
http://www.profilerperformance.com/r.../sbc-23-degree
With a 400 you need a Bigger Carb, at least a 750 CFM
Are you going to Go Roller Cam or Stay Flat Tappet?
I would go roller if you have the Budget...
I would do these Cams in this Order.... you need lots of Grunt with Those tires...
http://www.compcams.com/Company/CC/c...?csid=175&sb=2
http://www.compcams.com/Company/CC/c...?csid=166&sb=2
I ran this through Engine analyzer Pro and it Came up with 492 Lbs-ft @ 4000 RPM and 423 HP @ 5500 RPM... It Showed 412 Lbs-Ft at 2500 RPM. with a 750 CFM Carb