Which Head Should I Use?

Hey guys, I have a 1974 Slant head with the spark plug tubes, and a 1976 slant head without the tubes. ( i think they call those a peanut head?) Im getting an old style valve cover because i like the way those look better, and Im looking into getting a set of 198 (7.005) Connecting rods and different pistons to build a "long rod" Slant 6. While i like the 1974 head better, is one of these better for general use overall? will one or both conflict with my rods or valve cover? Thanks in advance Guys!