Will these fit an automatic?
will not fit an automatic
merge collectors have a performance gain to them due to exhaust scavenging effects. its not just a " show " item.
The purpose of merge collectors in conjunction with equal length runners is to use the scavenging effect. This effect is the process of each exhaust pulse that enters through the merge collector will end up creating X amount of vacuum behind it, which in effect pulls the next incoming exhaust pulse through the collector. This creates an effect which is continually making the exhaust velocity increase and engine RPM increases.