Visually the BMX crank arms look to definitely be based on Record forgings rather than the 144BCD GS arms. The flutes on both the arms and spider are machined in unlike GS, the logos and pedal thread stampings are identical to Record and the hole for the spindle on the inside of the drive side arms has the raised area surrounding it characteristic of Record arms of the period. The biggest visual differences between the BMX and Record strada/pista cranks seem to be that the inside of the BMX spider lacks the lathe marks (like the GS) and the polishing prior to anodization was usually-but not always- closer to GS spec than Record
I've made a page of photos of both BMX and GS crank arms so you can compare their similarities and differences:
Kurt Sperry Bellingham, Washington USA
On Wed, Mar 10, 2010 at 9:12 PM, Larry Myers <curmudgeon1957@yahoo.com> wrote:
> Hey-
>
> Campy supplied crank arms in a variety of anodized colors for the 80's BMX market; they were just Gran Sport road crank arms....the inner chain ring plateau was removed at the factory, and then the arms were anodized...also saw some that still had the inner plateau. Came in gold, blue, silver and red; had a set of gold arms on my Pogliaghi track bike, back in the 80's...
>
> Cheers,
> Larry Myers, Portland, OR,