Dan ,any sequence of production noticed between the different text styles that you pictured?
I don't remember, I wasn't in that frame of mind at the time. I was going through all the sets I had and some sets I borrowed trying to come up with a matching pair in similar condition for a Cobra completed in the spring of 1964. After doing some trading with people I borrowed from I traded off most of my better ones. I still have two or three singles and a new pair of reproductions that a person restoring their Cobra bought and then decided not to use.
I used one GT350 time period pair for my play engine.
It is really interesting that two people have old boxes marked with 1966 model year part numbers (S2MS-6A582-B).
Text in quotes below are direct quotes from the Shelby American parts book dated May 31, 1965. The numbers at right are retail and dealer prices.
Oil Fill On Right Hand Side : Cobras with 1964 HP289 engines.“C3RA 6582- B2 Valve Cover with Filler Tube R/H (Bud-B) Buddy Ea 17.97 14.47” (This was the second version. The number of the original version with chrome plated fill tube seems to have been lost to time, at least we haven’t found it, but might have been C3RA 6582- B. Both came out mid 1963.)
“C3RA 6582- C Cover, Rocker Arm LH Budy Bar Ea 18.68 13.08” (I believe, can’t prove, LH side PCV covers in Cobras with 1964 HP289 engines. For Cobras any raw casting could have been machined to be either an oil fill or PCV side.)
Others listed in the same parts book. Because this is a service part book we can’t know what might have been production, service, or both.“C3RA 6582- B4 Valve Cover Aluminum RH (1964) Ford (Buddy) Ea 24.75 20.13” (The 1964 notation is interesting. The original versions came out mid 1963, it seems SA defined them differently for some reason. I wonder what a B3 suffix might have been?)
“C3RA 6582- C3 Valve Cover W/Filler L/H (Bud-B) Buddy B. 18.92 15.24” (I read left hand fill as the GT350 application.)
“C3RA 6582- C5 Valve Cover Aluminum LH (1964) Ford (Buddy) Ea 24.75 20.13” (Again that 1964 notation is interesting. For some reason the suffix and price is now different with Ford being listed as the supplier first. Can’t help but wonder if the C3 and C5 suffixes are switched misprints. Service parts books can be confounding.)
“C4RA 6582- A Cover Rocker Arm RH Budy Bar Ea 17.74 12.42” (A new version which is listed for as part of the “S1MK 6582 Valve Cover Kit, For Mustangs, C4RA-6582-A, C3RA-6882-C, Gaskets, and Bolts Kit Pr 47.85 35.25”, I wished they had indicated oil fill or not after each individual number.)
My biggest unknown is when the last version of PCV side cover come out? Was it before or after the May 31, 1965 parts book was printed. Note that the S2MS versions indicated above are not listed in the May 31, 1965 parts book.