Take a picture of the bottom of the head and post.[/QUOTE] thats a good idea i can not remember all the casting numbers for all the gm bbc heads are they like the 929 cast like in my photo ? this head was used on alot of the 402 the 396 used a closed chamber we called them bath tub heads like 65to67. then i think in 68 to69 they trim more off above the spark plug then went to the 929 type chamber