Seems to me a lot of it had to do with chrysler not marketing it as a performance engine, mainly as a daily driver and utility block, so it never got the bells and whistles like ported heads, rollers and such. Kind of a missed opportunity if ya ask me since that's how ford marketed the Boss 302, but hey when you release a bunch of big block performance monsters like the 440 I guess you don't consider a 318 a performance engine :D