G-body LS headers

[SRD art]

Based on reading that others have used the F-bod headers in their g-bodies I traded some design work for a used set of FlowTech F-body LS headers for my 5.3 swap in my 79 Cutlass. I test fit them today and the pass side runs into the frame so much that I can't even rotate them enough get the flange up to the head, if that makes sense.

As you may have read in my build thread (link below) this car is my college Street Rod program project mule, so there isn't a ton of cash to spend on headers. Are there any products out there that will fit a g-body at a decent cost? I don't mind having to get painted rather than ceramic to keep it in budget.

To be specific about my needs, my goal is around 400 flywheel hp with a 5.3 pulled from a 2000 Tahoe. I will be using the factory intake system, 286 heads, have a decent exhaust system, and will be swapping in an aftermarket cam.

Honestly I'm so new to LS motors I don't even know where to begin, so any help is greatly appreciated.