Roinik;c-161556 wroteIsn't the 405 the eqivalent to the 531 and the 398 equivalent to the 530?
I was just reading about that. The 398 apparantely has smaller coolant channels(?) But the intake + exhaust ports are the apparantely the same and so are the chambers.
There was some mention on the TB forums about holes drilled into the 398 heads for k-jet injectors? Mine certainly do not have drill holes... is there any reason to keep them?
I'm wondering if there are any applications where the 398 head would be desired over the 530?