'64 Parisienne CS "barn find" - last on the road in '86 ... Owner Protection Plan booklet, original paint, original near-mint aqua interior, original aqua GM floor mats, original 283, factory posi, and original rust.
I can't say for certain but it almost seems to me I've seen a 307 head like that. Is the spark plug socket 5/8" or 13/16"? The early heads were 13/16". Those heads have to be at least 1969 or newer because they have bolt holes in the end.
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars
It's possibly a 1969 307 head or for a 1969 327 210hp (small 2BBL from Camaro) or 235hp (large 2BBL for full size). It is the 1969-70 equivalent of the 1968 3911032 (McKinnon 307 head) and the 3917290 (Tonawanda 307/327 head). These are both 69/70cc small port, 1.72/1.5 valve heads. As the casting mark is rough cast it will probably be a Tonawanda or McKinnon machined head, so possibly a 3927185 which is probably McKinnon cast as I don't think Tonawanda cast this head.
However the angle on the sides of the mark suggest another possibility. That casting mark was used across a number of heads from 1971-1974. Used on:
3973487 which is a 76cc version of the old fuellie head, used in both 1.94/1.5 and 2.02/1.6 valve versions.
3973487X (as above).
3986316 different chamber design and only 2.02/1.6.
3998916 basically as per below but only in 2.02/1.6
3998993 replaces 3973487. 76cc with either 1.94/1.5 or 2.02/1.6.