Technical Flathead head ID?

Im trying to help a friend out with a set of Flathead cylinder heads.
Stamped into this is 81 then 605049 and 79 in the upper corner.
Any help, or direction would be appreciated.
BKR

 

Pictures....they help....

 

I'll have to run out there and snap a couple....
Aluminum / no fins / Probably factory heads.

 

81 would indicate a 1938 24 stud design used with various minor differences 1938--'41 or so. It needs a suffix, as in 81A, T, or AS to identify chamber type (the 81 part just means '38 introduction for 221), and the number and type of threading of the small water ports would help set a year. Those heads of course are 24 stud, and are common and not really desirable for most purposes unless you spot an "AS" somewhere. Some will have full part number cast in on upper edge facing intake manifold...scrutinize that area.
"79" is probably just casting noise of no known meaning, though it would be a Ford prefix indicating a 1937 21 stud truck head if it were in front of a part number on a 21 stud head...

 

I think they are aftermarket replacements. Ford didn't just stamp their part numbers in the pattern. They used raised lettering. And the water port holes on the underside seem a little wonky, not nicely carved.

 

Agreed on that...but do look at the upper edge to be sure there are no cast part numbers.
Ford made 81A heads for several years, and another point is the number and type of small water ports, which kept changing. Early heads were only equipped for a single mechanical temp bulb, which gad a seat. later had electric, with no seat, and more portage was added in '39 for the new hot water heater...
81, also, is not a complete prefix, as there were 81A and 81T heads at least, and also the fabled 81AS...
The common versions are quite large chamber heads.

 

This is a Canadian head. It's embossed Made In Canada and it has two threaded bosses, 1 each side of the water port.
??????

 

Here's the picture.

I'm still learning how to use the app on Android.

 

Nice flatty and rare charger.

 

What are the rest of the markings on the Canadian head?

 

The Canadian part number starts with C7A......

 

Then that is a '47-8 Canadian, somewhat higher compression that the iron heads of the period. It should say Ford of Canada on there.
That head was reproduced with higher compression by Weiand, the "cheater" head...I think the one shown is real, though, casting looks too good for Weiand.