jlr,
The Master Parts & Accessories Catalog (up to 1954) gives a casting number of 3835517 for 1941-1949 235 heads and also for 1941-1953 216 heads; 3835908 for 50-52 235; and 3701887, 3701886, 3710359 for other 53/54 235s.
I do not have numbers for 1955 and later 235 heads.
It is possible that someone put adapter bolts in the rocker assembly of a post '54 head so that an earlier valve cover could be used. If that is the case, there would be 4 machine screw holes in the head under the seating edge of the valve cover (these holes are for the '54 and later valve cover hold-down bolts). Are you easily able to lift the valve cover to look for the four machine-screw holes?
If you can lift the valve cover, compare the bolt pattern to those at the following link (sorry about not having casting numbers):
http://www.inliners.org/tech/tech5.html Tim
