[John Brown]

D309 was superceded by D309R in 1969. Had something to do with FCC requirements for static/radio emissions. Both numbers were brown (at least earlier production was) with copper terminals. D309/D309R caps were used with T.I. ignition and on heavy duty trucks. IHC, White, REO etc. Most of the black D309R caps I have seen came in red, white, and blue Delco zip top boxes with the blue painted steel tops. Most of the old orange and white boxes with the black painted tops still contained brown caps.