I don't think people realized the 337 was any good until about the same time MP decided to quit making them. I don't know what they sold for new "way back when", but popular used BB Mopar intakes seem to be bringing good money these days.
That was back when Zippy was still working at MP. They killed the 337 and then he talked them into bringing it back. I did some dyno tests with it for a magazine article and made really good power. They sold a few more after that and then killed it again. They really just didn't want to sell parts like that anymore no matter how good they were.
