Big block header decision time... help!

[.030over]

Getting close to think about headers so I thought I would kick some options out to see who has tried these. What I am building is a '67 SWB that will be lowered 4/6 or maybe 5/7 so I need some ground clearance. I plan on making a custom trans crossmember and will route my own exhaust. I mistakenly bought a set of std heddman headers for this truck only to hear you guys all say they don't have enough ground clearance. So my options seem to be (1) some type of pass car long tube header that has higher collector exit (chevelle, camaro) or (2) use a shorty header that won't maximize my 500hp big block. Has anyone used a mid length header on a big block? I see the small block Chevelle mids work but don't recall seeing anyone use the big block ones. Anyone use full long tube Chevelle big block headers. I know they would interfere with a stock trans crossmember but I can fab it however I wish. Any other ideas guys?
Thanks,
Scott