Chris.
Bottom spark plug hears are very rare as the concept proved to be too difficult to use in a production chassis. The first design rocker arms were all non adjustable and valve lash was adjusted with small "lash caps" placed between the valve tip and rocker arm. Setting lash took ridiculous amounts of time and the second generation adjustable rocker arm was developed. The style of rocker arm is not unique to the iron or aluminum head, The interchange. Most (for obvious reasons) go with the adjustable rockers used on "most" of the (potential at the time) production engines that were eventually sold off through Holman Moody as many period pictures document. Aluminum heads were very rare ( some accounts say 50 pair and others say less) and only a Ford "contract" racer could get them (initially). I am nit picking but since I was around in the day , the only engines to get the black valve cover stripe were those that were painted the "gold color" . The "Blue" engines had blue stripes on the covers. The blue engines were built for '66 production vehicles ( though we all know it didn't happen) which were all painted corporate blue. That is another reason the physical parts don't match the description of the car.
The issue with this '65 isn't the parts , it is with the "factory built" part. A car that was modified like this would have a "brass tag" and be noted in factory paper work as being done by the ''Stock Vehicles Dept", IF it was done at Ford as a prototype. The work is top notch and it IS possible it was done by DST who was very capable of doing work of that quality for "any" customer. "MY opinion ONLY" s that this car was probably done at DST and possibly for a Ford employee. I have ZERO proof , just a hunch. Dearborn Steel Tubing is still in business and "I" would encourage any potential buyer to check with them to see if they had anything to do with it. they "may" still have those records stored somewhere. they built many specialty cars for Ford besides the well known Fairlanes and Comets of '64 and '65 ( yes they built 2 '65 Fairlanes , 1 cammer and 1 289).
Randy