Trying to help CORONETGIRL's Dad with his cracked cylinder head on his '61 361 engine. The car has 324 heads and one head has a crack in the chamber by the spark plug hole. Looks to be at least 1/2 inches long.

I don't feel that welding it would be a viable fix. Not sure if you can stitch weld it or not.

My suggestion was to go with the newer style 516 heads. They have the same valve sizes and chamber CC but would need modern valve train (the 324 has flat rocker pedestals).

But we are seriously confused. The 324 head has 2 additional approx 1/2 inch round water passages in between the intake valves the the 516 and 906 heads don't have. From the look of the head gasket, does appear that there was water flow through these holes. Cannot find a new head gasket that has holes for the additional water passages.

So I figured that only the older heads had the additional passages, but then I noticed that my 452 heads also have those additional holes but they are not round (see picture).

So the question on the table is what are the additional holes for and is there supposed to be water flow through them or not? Is it safe to use a 516 head without the additional holes? I figured worse comes to worse I can drill the additional holes in the 516 head and the head gaskets.

Any ideas?