From my point of reference it was a late 1964 / early 1965 race only intake that did not require a PCV system connection point. All 1963 onward engines in Shelby American regular production street vehicles would have required a PCV system. The balance passages between left and right sides was a modification Shelby American used in road race 4V COBRA intake manifolds 1964-1967. Yes, privateers copied the balance passages after a magazine article was published on the details different between a street and race GT350 engines when the cars were new. Just having the spot faced passages alone does not mean it was "factory" prepared.
Shelby American used and sold several different COBRA lettered high rise castings between 1964 and 1967 not ready to use with a PCV system. Buyers could even order complete 4V race engines mail order and for a while through selected speed shops.
The version shown in the original post was apparently fragile as every one I have held or seen pictures of except two were repaired from a break some place or another. I have a new old stock one that the buyer of a 1964 Cobra owner bought after delivery and never got installed; he sold it to me. The other was installed in a 1965 Cobra for the owner by his local dealer and it is still intact. That car was fit, by the dealer, with a custom road draft system for crankcase ventilation.
There was a thin engineered material heat barrier and PCV adapter spacer Ford had available that would have made adding a PCV system to the engine very easy.
C2AZ-9A589-E
The market value limits have been from my point of view 1) no factory street car used them that we know about and 2) every one for sale in public so far has been broken in the past and sometimes modified in some way. I had one that had been broken and repaired so as to not be detectable. It took quite a while to find somebody that wanted it at any price and I did not make it to break even on that sale.
Shelby American used and offered only two versions of a single 4V aluminum intake, without or with COBRA lettering, supplied by Holman-Moody of their design for 260 and 289 engines all of 1963 and through the mid CSX24xx chassis range Cobras in 1964. It was physically functionally a copy of an experimental 260 iron Ford intake manifold from 1962.
Street use ready for 1963 and 1964 engines, C4SA-9421-1 optional aluminum 4V intake manifold for Cobras completed in 1963 and 1964.
Shelby American did not offer a High Rise COBRA intake in a new street Cobra until after 1965 had started and then they used GT350 intakes from 1965 model year run. Only two very late near the end of production new Cobras received factory installed 1965 GT350 induction systems (intake and carburetor). They were CSX2553 and CSX2555. CSX2588 was the last car sold to the public and CSX2589 was the last Cobra retained by Mr. Shelby until his passing. CSX2553 was invoiced on January 21, 1965 and CSX2555 was invoiced on April 21, 1965.
