I got to thinking last night after I posted that it is irelevent wether its a B or RB, I am concerned only with the spark plug interference. The relationship between the headers and the plugs is the same on eithier motor. If the headers clear the angled plug configuration on a 383 they will also do the same on a 440, am I correct in thinking this. Having said that, does anybody have any pics of a set of ProParts headers mounted up to the Performer Heads?