They make a nice set for a-bodies with b motors (383-400). They go in in 3 pieces and supposedly install very quickly. 2" primaries and 3 1/2" collector. They don't work with 440's. He supposedly has a 1 piece header for 440 cars coming out. He has a small operation in southern mich. you have to call and order them and then wait for him to build them. Last i heard they were around $550. When I get my BIG block done (summer), I'm gonna get a set to replace my schumacher's.