Tech, there are five HH listings in my MSA-1 book...the three you listed plus 1967 300 hp 327 in a corvette and a 1968 Imp 327, 250 hp powerglide

The 3947041 Head casting number is listed for a bunch of applications
68-69 302 with 2.02 intakes
68-69 327 300 hp with 1.94 intakes
68-69 327, 325 and 350 hp with 2.02
68-69 350 295 hp with 1.94
68-70 350 with 360 and 370 hp 2.02

some of these listings are interesting since they span the heads with and without bracket mounting holes in the ends of the heads

mike in tucson