Further research in the parts book indicates the LH side rocker arm covers were the same from 1957 to engine # 1585 in 1958. Probably using up the supply of 1957 covers. Several other posts indicate the '58's had two hydraulic (engine) oil return line connections in the LHS cover--from a heater door!--This in addition to the coil-mount bracket. Now I wonder if ALL the solid lifter hemi rocker arm covers were modified plain vanilla New Yorker covers. A set of dies to punch up the four high spots/bumps for the short runs of adjustable rocker arm engines may have been far cheaper than a complete new set of dies. I recall that Imperial and industrial hemi's had different stamped lettering on the covers. For you 413 only guys & gals that may be curious, I just received a good photo of a '55 rocker arm cover with the bumps and can send you that file, or maybe post it on our server??? Perhaps now we can debate/clarify whether the oval-headed machine screws fastening the spark plug wire covers to the rocker arm covers should have straight slots or Phillips-head. I've seen some indication there was a mid-year change. My early '55 had chrome-plated slotted head screws which I replaced with very similar SS screws from Ace Hardware (special order). I also ordered SS star washers and formed them to fit the tapered screws with a screw and a female wood die. Or, not. C-300'ly, Rich Barber Rich, the 57 and 58 300 valve covers have a spot welded on coil mount, there is a small difference between the 57 and 58, one leans more towards the rear of the cover, placing the coil a little closer to the power brake booster, the other leans the mount towards the front of the cover giving a little more space between the coil and the booster. There is a swap meet vendor that has started to make (modify) 'bumped' covers, a reasonably decent job of replicating the factory bumps, BUT NO coil mounts. -- Paul Holmgren Mine: 2 57 300-C's in Indy Hers: 05 PT GT R/T HO Stage 1 Hoosier Corps L#6 ------------------------------------ To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/Yahoo! Groups Links ------------------------------------ To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/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: http://docs.yahoo.com/info/terms/