Originally Posted by
squirtdad
not to confuse this much more, but early 80's or late 80's? and what vintage cranks? early 80's BB and cranks are different from later cranks.
The CPSC change to Record/Super Record was made in 1978, with the aforementioned change to the BB spec.
Record crankarms were made for several years past the introduction of C-Record, but the BB spec did not change. Gran Sport alloy arms of the era use the same BB spec as Record, but with lower-quality parts.
As already noted, the C-Record is a completely different crankarm with a completely different BB spec.