The white insert on the ID of the stem seal is teflon. Those are 1 version of a "PC" Perfect Circle, seal. There is also an all teflon version with a metal garter band on the od. I measured spring seat diameters on a 690 & 583 head, both were 1.470 ish. Measured spring od on a 817 head it was 1.2/1.22 ish. Parts book lists 2 different oil shields for LP & HP applications. 3836755 is for LP and parts book states 1-3/8 od. 3795664 is listed for HP, 2-4 bbl applications and parts book states 1-5/8 od which should/would probably fit a 1.450 od spring. So with this info 690 & 583 heads may have 1.450 od springs as standard outfit.
Jeff