Matt,As we don't know where the restriction to running the "normal headers" is, posting some pic's yourself can help. I would suggest looking into maybe thunderbird headers as these use a similar engine mounting to you. These could be good as Tbirds don't have much space. Also Tim McMaster posted some pics of the LSR pick up with factory sedan duals swaped side to side in one of his recent posts. Can you run duals from the front and under, is the restriction centre dump or where?
A good question draws a better answer.
Cheers
Warren