You can also look back on my build thread Mark....and it wasn't that hard! Think I still have 100 paper clips I could send you. Just take your time and heat/stretch all the fold marks out...
If you have purchased the headliner already, do yourself a favor and immediately unfold it and store it rolled up instead of folded. Sitting in a box folded up only exacerbates the creases.
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72 Nova SS - Minitubbed 70 Nova SS - #'s L-78 Bench Stick 68 Acadian SS clone - factory air 67 Chevelle rag - SS 427 clone