Small block headers

[Lou1119]

What is the difference (s) between 302 and 351W headers? I've been told the 302 header pipes have round inlets to match the heads and the 351W pipes are rectangular .

Thanks

[Mark IV]

Length of primary tubes as 351 is "higher" and therefor the headers are different. The ports are the same basically. 302 headers on a 351 will put the collectors a couple inches above where they need to be and vice-versa. They can be modified to work either way with tubing and a welder.