I have been “ fooling around” with 3-4 distributors , sort of a side project by accident , initially launched by trying to straighten out a really beaten up F distributor . First, I now know —for sure — that the advance slot in the part with the point cam definitely varies in length by car to limit advance . 300F .39” but a 55 plymouth one — brand New is .48” . This has huge impacts as a lot of mechanical advance (!long slot) forces one to less initial so you do not end up with way too much at high rpm . Realize you cannot “ add initial timing” without going way too much high up !! = Piston hole! Thus F had a factory “Hot rod “ tune ,significant initial and very limited mechanical , very light spring ... .so mechanical all in fast, probably by 2500 rpm. - 2 Nd spring ( high rpm) so beefy I doubt it moves . Note that second spring has loose loops as assembled so first one can move . Takeaway : identical appearing point cams and slots are not . Unique to car tune . Never swap . P stamped on this F one ,Q on plymouth . Heads up . Second , for sure — hole in vacuum advance arm wears egg shaped , that kills you as initial timing can dance around — as can the whole timing curve at WOT due to that play . Vacuum arm is relaxed (in ) at WOT , it is all that keeps breaker plate in place rotationally — the can arm (!!) — And that fit .. hardened pin in plate but too small diameter , soft steel arm wears . Later mopar have larger pin . They knew . Third , casual check of it with rotor on , the rotor hits cap terminals ! YOW . Disaster that is . Whole point cam , and thus rotor can move up and down maybe .125 . Cannot be right , although have noticed vertical play there before . How much ? This cam plate (on both of them) has a little sleeve welded under , while later have ( I think ) a flat underside and a Loose Spacer. Same prurpose ? Or supposed to be a spacer too on F ?? ? But spacer only stops any downward motion — not upward , which is what causes the hit. I think maybe should be a spacer washer under that damn impossible to get off wire clip ? Started to make one ,to Keep rotor down-for sure . But decided to ask first on site . Maybe parts were missing on my F dist . 75 w Mobil one really freed it up , grease is a sad joke . Heavy Oil mixes with grease we are really good Related , rotor fit to metal stem seemed very loose ; there is a flat “hat like “ top on the spring steel flat retaining spring inside the rotor , has a tiny projecting clip that snaps sideways into a slot — only if the “hat “ is pushed in all the way , and flat . That was wrong on my rotor , not seated . Looked like factory built it wrong . Fixed that ,but that made flat spring part on side sit really flat , rotor did not grab metal shaft well at all .. rotor could drift up !! Disaster again . Fixed that . Bent out side flap with tiny screwdriver — I have seen tape , paper etc Jammed in there on this,so beware . Will wipe out your cap and wires = big mess . Rotor fit should be vertically tight . Now it is . Should take effort to slide up But now left with what seems like too much up travel, on whole point cam and rotor toward the retaining wire clip — and noticed this much up starts to lose advance pin engagement below.. cannot be right . If no concrete answer going to make my spacer under retaining spring . And what to do with a good F vacuum can with egged hole. A Drill bushing or something ? All this very subtle and new info to me anyway . Thought I would share for comment and info. It is important to a good running car . That vacuum egg shape thing might lead to wandering idle , something I fought with minimal success for years On ram cars , — as vacuum can is active / moving then .. timing change = Idle rpm change . FYI , John G Sent from my iPhone not by choice ------------------------------------ Posted by: John Grady <jkg@xxxxxxxxxxxxxxxxx> ------------------------------------ To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx To unsubscribe from this group, send an email to bob@xxxxxxxxxxxxx or go to https://groups.yahoo.com/neo/groups/all/manage/edit For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/search.htm#querylang ------------------------------------ Yahoo Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Chrysler300/join (Yahoo! ID required) <*> To change settings via email: Chrysler300-digest@xxxxxxxxxxxxxxx Chrysler300-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo Groups is subject to: https://info.yahoo.com/legal/us/yahoo/utos/terms/