What headers will fit???

If the Doug's didn't fit, I doubt the TTi's will.

Exactly. The Doug's should fit. They fit my '74 Duster with a 340,Milodon road race oil pan, 4 speed with all the mechanical linkage, etc. The only tight spots are at the torsion bars, but I have 1.12" torsion bars. Doug's 453's should clear the stock power steering unit. Not sure about that particular oil pan, but the steering box should be in the same place as every other power steering box.

Why are you running Schumacher mounts with a QA1 K-frame?