Posts by Dan Case

    Thanks Dan, your information is always appreciated. This photo is after a dip in the ultrasonic cleaner and vapor blasting, but you can see the scratches on the fins that will need to be removed as part of the polishing effort.


    To make them pretty just takes a little time mostly. Reworking them to look like Barksdale's company made them is a lot of trouble; ditto all the aluminum intakes they made or the intakes made by Offenhauser. 1963-64 made parts have evidence of many steps, multiple mill table set ups, and lots of hand work. The covers made for Cobras with 1964 model year engines were all made off a single wooden master pattern. Raw castings were cleaned up with hand files and machined to create oil fill tube and PCV valve versions. The insides were chemically polished to a slick surface. The outsides were media blasted to create a fine dull matt finish and then sealed by something. Raised appearance side features were polished. Oil fill tubes appear to have been hand made in a set of processes that cut pieces of preplated steel tubing to length and added the SAE type beads with something like a Parker® tool set. It appears some type hand tool was used to lock the oil tubes in place. Unmolested oil fill tubes have all the evidence of all the steps required to make and install them as artifacts.

    Circa January 1965 the whole manufacturing scheme was changed and many fewer steps were applied. Multiple new wooden patterns made to revised designs so that oil fill and PCV sides got their own castings meant less machine work was required on raw castings. Oil fill tubes were redesigned and became machine made it appears. The internal chemical polishing was dropped. The external matt texturing remained but to me the covers made 1965-66 were much more variable in appearance of the finish with some covers being quite bright fresh matt aluminum day one while others could be a medium gray color.

    To the broader audience, be aware that many cover sand castings have lots of small gas bubble voids in the aluminum. Harsh solid media blasting can enlarge voids that were exposed during original manufacture and break open voids just under the surface. Once whatever raised features finishing is done these little pits can be anything between hardly noticeable to very noticeable depending on how many and how large the pits are. Polishing compound in the pits shows up as dark spots.

    Top restorers avoid making visible pitting worse than it was day one.


    To make them look something like they were the day made the exterior (less plated steel parts) would be given a very fine matt finish through carefully selected aluminum oxide media first.

    Then the just blasted surface would be sealed chemically. Some people use a modern corrosion inhibitor product to fill the pores in the metal; there are aqueous and non aqueous versions for sale.

    As manufactured type process.

    Then the tops of raised features would be machine buffed with something like a cotton buff and soft metal stick type polishing compound taking care not to push the buff down between raised features. Originally the tops of raised surfaces had as close as one might get to a mirror finish in a job shop production situation. All polishing would be lengthwise as much as possible.

    Remove any polishing compound residue. I just use WD40® lubricant and a soft cloth most of the time on polished parts.

    Hand polishing type process.

    I have repaired unrestored polished areas, usually tarnished by something like anti-freeze solution or battery acid, by hand slowly. 600 wet or dry paper wetted with soapy water or WD40 lengthwise of the part. Step wise repeat with finer grades each step to at least 2400 grit. Then your favorite magnesium or aluminum polish can be used with a thick rubber sanding block wrapped in fine weave cotton cloth or thin rough leather until the desired surface finish is obtained.

    Maybe they were cheap and seemed like a neat idea. I know somebody that bought an excellent used ex-factory race team set for $100 delivered circa 1980.

    Without full competition modification to go with them the C6FE heads might even be a step backward depending on the combustion chamber sizes. The chambers are larger than the chambers in stock heads as cast and can get larger during any reshaping and polishing work without milling the decks to reduce volumes. SA often used steel shim head gaskets or o-ringed decks with C6FE heads. The limit to them is still getting exhaust out.

    Just started a full rebuild and found i have C6FE heads on my motor, just how rare are these?

    Original 1960s ones, pretty rare. 1960s ones that have never cracked and required repair, even rarer.

    Mid 1970s on reproductions, not all that rare and new made ones can still be obtained.

    You will definitely receive differing opinions on this subject. Having done this same upgrade in the past, I did not experience any large gain. Keep in mind that another part of the upgrade on 65 and 66 Shelbys were the Tri-Y headers. I did not add those.


    +1 Fred

    Some comments.

    - I will add to Fred's MUSTANG GT350 comments. The 1965 cars also used straight through very low restriction glass pack mufflers and for most states very short side out exhaust pipes for free exhaust flow.

    - Larger volume intake manifold and larger volume carburetor normally means a little more sluggish low end while pushing the engine's power band up to a higher rpm range. Shelby American assumed buyers were competition minded and assumed they would be running up to 6,500 rpm frequently.

    - For testing Shelby American had super premium, usually highly leaded, fuels that users could also get somewhere close to where they lived. Their highest numbers used in advertising were obtained using special leaded race fuel, no alternator, no air cleaner, dynamometer room headers, and BF603 (very cold) racing spark plugs. If your engine block decks or cylinder head decks have ever been milled the static compression ratio went up unless something was done with pistons or head gaskets to prevent the increase and higher pressures make fuel choice more important.

    - Shelby American normally, based on their engine test reports, used a total ignition advance of 36°. Some users now find that too high these days; goes back to fuels available. Every engine, exhaust, and vehicle system is different and so are driving requirements and styles so one setting may not suit everybody.

    - The Ford 4100-A carburetors are generally regarded, some will disagree, the best 4V carburetor ever produced. Being a smaller carburetor than the GT350 one the velocity of air and then air/fuel mix will be faster and that is a good situation all around especially in the low and mid range. How many times does one run 5,500 rpm and above these days and for how long?

    There are lots of pros and cons about going to an aftermarket larger volume induction system. The whole topic is way too long to cover in little text boxes in forums.

    Apparently an escapee from Ford development. My information table indicated they had two sized of throttle bores 1.23 and 1.19. Some speculate it was an attempt at the "spread bore" concept. I have never found any data on SAE corrected air flow. One was for sale on eBay(R) not all that long ago. It was not a production model. There was a 1.19 production model in the 1950s that was very rare then and super rare now. Some big block engine folks hunt for the 1.19 size models.

    Still depends on location (altitude mostly) and of course vehicle specifics and driving styles.

    We live at 5,400ish feet above sea level now. In addition to lower oxygen content the relative humidity is often very low (8 to 23% has been common this summer). A day's outing might cover altitudes between 3,500 feet and 8,700 feet above sea level. Our black car got a dealer installed COBRA 4V induction kit and linkage kit for a Cobra circa early 1968. I retuned it for this area when we moved here and it was very nice but not as crisp in throttle response and felt light on torque in the mid range here as compared to in Alabama. I cleaned up a C4OF-AL and prepared it for a Cobra at this altitude and got back to crisp drive away and instantly responsive low to mid range tip in again. The R-3259-1 Holley® was okay but even more "too large" at this altitude. Yes, I am sure ultimate power is down with a smaller carburetor but I don't drive around zipping up to 6,000 to 8,000 rpm any more. Now it is more important to me for the engine to be super smooth under a wide range of conditions and immediately responsive. (The Holley installed decades ago is being kept and may go back on if I get to where I cannot drive the car much anymore. I have already serviced it for a return to duty.)

    Depending what early means assembly line parts could have been three rib insulators early and five rib late.

    Car restoration wise the cylinder heads could be interesting for somebody with a 1967-68 Shelby Group II Mustang, 1965-66 GT40 MKI, or 1967 Bud Moore Group II Cougar.


    I never kept up with all the race only cylinder small blocks Ford made after 1965 and there were quite a few before Ford quit factory racing after the 1970 season. Some were not such good ideas. Some were raw materials for independents to machine any way they wanted. Some like the 351 Mirage made one of the strangest engines I have ever seen in period.

    I have asked somebody that might know more from the poor description posted.

    How would one determine witch one I have? All I know is they were open letter, have the “buddy bar” stamp and some knucklehead painted them orange…I can post a pic when I get home. I figured they were period correct for my 65 and authentic so I bought them to match the 3 Duce I’m installing on the car

    Every wooden master pattern resulted in unique castings, i.e. every wooden master was different in some ways a little or a lot. There was only one wooden pattern in 1963 and 1964 for 1964 engines. It gets more complicated in late 1964 as the first MUSTANG GT350s used parts from the aborted production of Cobras. During 1965 several new wooden masters were carved and from then on several versions of castings followed. Oil fill tubes changed multiple times also. The last part number created was introduced in May 1965.

    I have a large slide show I created that has details and pictures of all the 1963-1964 Cobra part versions and some details on the ones made 1965 and later. If you want a copy send me your email address in a message through this site. The current slide show has 29 pages of information and illustrations.

    Parts made in 1963-64 for 1964 engines are tough to find and sought by Cobra owners and restorers. I have hunted for a PCV side cover that was suitable for an unrestored 1964 car since 2004-2005. If one you have turned out to be a 1964 part and could be just gently cleaned of paint I would be interested in finding a 1965 replacement to make some kind of trade arrangement.

    Thank you Dan this was exactly what I was looking for…BTW I use aluminum oxide in my cabinet. But it appears I may want to dry ice blast these and I had never even herd of that process. I also am pleased to hear the ribs were high polished as that is what I wanted to do

    You are welcome.

    You might want to determine what version of parts you have before doing anything. The original 1964 model year covers were made as production parts for new Cobras. The assemblies Cobras used are rare as loose parts and extremely rare in never damaged or media blasted condition. I have been looking for a PCV side cover since 2005 that is totally unmolested. The covers were sold by Ford as accessories for other 1964 Fords but it must not have been a popular purchase. Circa January 1965 more than one of wooden master patterns started being used and before new 1966 MUSTANG GT350s changed to using the new die cast covers other production revisions happened.

    Hey gents I’ve got a set of buddy bar open letter valve covers that I want to restore, they have been painted on etc…I do not want to ruin the value of these things so I am going to ask if anyone has done this and if you can give any pointers. I was planning on sand blasting then polishing the fins however after reading on a blog I noted someone more schooled than I mentioned one of the ways to tell a re-pop from authentic is the re-pop is too polished. So I guess what I am looking for here will blasting the aluminum or polishing the fins hurt the value? If it’s ok to blast should I put anything on the raw aluminum to protect it and how polished we’re the fins after manufacture…will just a light sanding and hand buffing work or does it require polishing on a buffing wheel. Thanks for any info :)

    Originally all the sand cast 1963-66 “COBRA POWERED BY FORD” rocker arm covers and oil pans for Cobras and Mustangs were chemically polished on the inside while the outside was a very fine matt finish and all the tops of raised features were highly (almost mirror) polished. The exteriors were also treated with some type sealer to help fill micro pores in the exteriors and retard corrosion.

    I would not recommend glass bead blasting any engine part surface that is open to interior of the engine. Some beads break during blasting and microscopic shards of glass stick into the metal. The tiny pieces of glass will over time fall free and get into the engine lubrication system. The affect is like putting grit in the engine on purpose. Sand blasting with silica sand is worse. Inside surfaces can be media blasted with dry ice, metal shot, or something softer like walnut shell or baking soda media. Dry ice blasting is the only media blasting method that makes zero changes to the surfaces being cleaned but service providers are few and far in between.

    Assuming a casting has not yet been media blasted by anybody, any hard media blasting has the potential to make the parts less desirable for top end restorations now or later. (I once followed a thread as somebody took a $3,000 Cobra part and turned it into a $600 Cobra part after a few minutes of glass bead blasting.)

    Exterior wise, the oil fill tube and brackets for spark plug wire loom clips have to be removed to do a great job on the exteriors of the castings. The baffle on the oil fill side has to come out to remove and replace the fill tube carefully. That is also the time to do any metal work repairs to the steel parts and get them replated. Some shops discard the original steel parts and install new reproductions. New rivets have to be purchased. A lot of people will not care but high end customers probably don’t want reproduction bits you can see on the covers.

    I am working on some aluminum cast parts that originally had a very fine matt finish like the rocker arm covers in question. I bought a small bench top cabinet and have been experimenting with different size grades of aluminum oxide ‘grit’ and different air pressures to recreate the 1960s matt texture. Small test samples look very promising. I will do more testing on scrap before an ultra rare part gets done.

    Top restorers use all kinds of chemicals and protectants to seal the pores on the exterior of aluminum and magnesium castings as a last step. I have heard of WD40®, LPS3®, Gibbs Oil®, Boshield T9®, and others being used and people being happy with the results. Gibbs Oil is widely used to help seal magnesium part surfaces (works best for me).

    "NOS" means "new old stock" never used never installed to most old car fans. This intake shown in the auction offering pictures has been installed and shows the evidence of water corrosion on the exit port faces as if the user did not include a corrosion inhibitor or anti-freeze that contained corrosion inhibitors.

    PS In the Cobra roadster option or the Ford over the counter accessory the intakes are the easiest parts to find and the lowest cost major part. Example: A matched pair of original air cleaners might cost in the four digit range as cores that could be restored.

    I just tried sending a test message two ways through the site, one as a "Comment" under your profile page and one as a linked email.

    Hi Dan, i think there is a large error in your profile printed under the picture of your cobra ,it says ( student) there is no way you are a student in regards to what is talked about and information about any area here on the site , you and Fred are the most knowledgeable guys around, thanks for sharing , regards, chuck.

    Thanks but I have no idea how that came to be. Everything was blank on the edit profile page.