Ronnie is correct, they made the raised intake surface blocks in both 221 cubic inch Ford sizes as well as the 239 cubic inch Merc, Truck and WWII production versions.
Another term for them was the 'Keystone" block -- with many tall tales about how they were thicker, had more nickel content, made hair grow on bald heads, that all the "chicks dig them" . . . you get the point . . . lots of urban myths!
I've done quite a bit of analysis; I've managed to corroborate none of the myths - especially the last one mentioned above.
