I'm about to fabricate some cooling ducts for my '85 in preparation for the 1st SCCA race at Texas motor Speedway July 12-14. Rather than go the easy way and get the Mazda Comp backing plates, I'm going to do it the hard way.

Caliper end - Looks like I can weld a 3" tube at about a 45-degree angle off the stock backing plates and then open up the stock holes.

At the front the stock black sheet metal "duct" is already opened. I intend to attach the hose there with some wire stitching and fill the gaps at the outboard end with spray foam or something similar.
Ideas or suggestions, caveats before I get started?

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