Working with 3D printing replacement early A-body parts

I would be surprised if the 3D printed parts are going to hold up all that well. The materials that are 3D-printable make it difficult for them to hold up long term in automotive environments. I could be wrong, but don't get too hopeful.
Was thinking the same, with plastics its difficult to say but if the right stuff is used etc. High heat it warps wrinkles in the cold cracks etc.