Cool. My memory is rapidly waning on my old XE Falcons head. I removed in it 1997, and it was the standard head which some utter nong had sandpapered backand reapplied the stock Monotorque gasket and torqued back up. After a radiator leak, it blew a head gasket, and ignited number 5 chamber so bad, it melted the metal around the valve insert, and yet the valve was still in place. It was rewelded, remachined, and was still on the car when it was sold in 2003.
(That's why I say the alloy head is a good bit of kit!)
It had notches, what is in fact a closed chamber head like all X-flows ran. The C1, C2 and E1, E2 are kidney shaped heads, still closed chamber.
There has not ever been an open chamber Ford X-flow head, as they are all copies of the old 302 Clevleand "Quench" heads, with chambers downsized for the smaller valves and narrower cylinder bores. The open chamber 351 C heads were entirely round, all the early X-flow heads have a quench zone on each side, which stops them being an open chamber design.Best way to describe it is that all pre 1985 heads are more open chambered than the later ones.
The head on my old XE was not the later kidney one, and was in fact an HF 5 closed chamber head. Just like one of the engines in my garage. Top is a picture of the old iron 1977 XC iron one, bottom is a 1984 HF 5 alloy head.
The intakes for HF 1, HF4, HF 5, and C1 or C2 heads can be any type of C1, C2, C3 casting, but the best are the two barrel ones like this..
After market ones like this one for Alloy heads and Holley 2300 carbs are common
The iron head x-flow won't fit the later intake, so you often find ones around like this
In normal form ,the iron head x-flow and the first alloy head with the 1-bbl carb looks like this
The later alloy heads had a different mounting face, like this
The chamber cc's went from 53 cc down to 49 ccs from 1976 XC to the last 1993 XF.
Above, the XF EFI head, below, the earlier HF 4 carb head. Note the difference in chamber
shape . Both are closed chamber heads, but the carb head is more closed
The earlier carb HF 4 head is like this