I've got a 400 at the engine builders getting done up with a 440 Source rotating assembly and I've come to the point where I need to start ordering all the bolt on parts. The motor is going into my Fifth Avenue (an M body) and I didn't anticipate there being large tube headers that would fit, so I'm looking at shorty headers, but can't find any that are swept back to clear the gear box that have at least 1 3/4" primaries and a 3" collector. Everything I can find only have a 2 1/2" collector. Do they make such a beast?