Hi Harry . . .
Not much expertise on 12 ports - but I know my way around the online archives of the club. Here's an old page with a listing of owner/location of
known 12 port heads.
#1207 is listed in the cast iron Chevy section. One thing I do know is that the original 12 port heads were cast for use on the dipper/jet engines (15 head bolts). The new design head for the Corvette 235(full pressure) has 18 head bolts. Many of the 15 bolt heads found homes on the older 235 Hi-Torque engine - and some even went so far as to rifle drill the old cranks.
regards,
stock49
