Did this for a another board, perhaps it could help someone here.
Went and measure one from a 79 and one from a 74
depending on where I measured, all measurements varied about .0625 or 1/16" roughly
74. same as 70-74
overall dia. 14.25" +/- .0625
thickness of foam. (perpendicular to stitching. ie. front to back of car) - 1.125 +/- .0625
79
same as 75-81 except pace car and 10th anniversary. they follow 70-74 measurements. grey in color.
dia - 14.074-14.1"
thickness of foam. (perpendicular to stitching. ie. front to back of car) - 1" +/- .0625
hope this helps
