Dan ,
You can add a 90* aluminum 3/4" or 1" strip or pieces to the fiberglass blank with mounting holes pre drilled for the underside of the dash after the blank is released from the buck . Just glass them in . Probably wouldn't hurt to add larger holes to the side that bonds to the blank so the fiberglass has a stronger grip on the blank .
The fiberglass will give you general shape and structure , then "Bondo" will give you close to final shape , then lots of sanding to refine the finished shape . Now your ready for paint .
You've got this , have fun with it .
__________________
Glen & Jane's Rides
‘57 GMC NAPCO Long Bed V8 4 speed Bought 2008
7 other cars & trucks , 5 trailers
'56 Chevy Long Bed I6, 4 speed Bought 1990 Sold 8.22.2020
’56 GMC Suburban Pickup V8, 4 speed Hydramatic Bought 1996 Sold 10.11.2020
My Other Tinkerings
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