I have talked with many people regarding exhaust and headers. All that I
have spoken with recommend the 4-2-1 header for torque (lower RPM power) and
the 4-1 header for high RPM power. My car has a 4-1 header that I don't
like very much. I believe the cast iron manifold flowed better at lower
RPM's than this header. I recently installed a Maniflow exhaust on the car
and really like it (sounds great). APT sells the Maniflow exhaust and
header (4-2-1). Next year I'll get the header from APT. BTW I have no
interest in APT but I think they know what they are talking about. Make
sure you decide what it is you want the car to do and then make a plan.
That way you'll avoid buying this twice (first the mistake and then the
correct part....I know this well).
'70 Mk3 Spitfire
From: Vic Whitmore <firstname.lastname@example.org>
To: Spitfires Maillist <email@example.com>
Date: Tuesday, September 19, 2000 8:24 AM
Subject: 4-2-1 Exhaust Header
>Hi, everyone. I'm interested in putting on a performance exhaust header as
>of my plan to build towards a performance gain in the 1500. I'm looking for
>advice from those of you that have 'ben there dun that'.
>Who has a 4-2-1 exhaust header?
>Where did you get it?
>Who made it?
>What was the cost?
>What problems did you encounter during the installation?
>Are there any real differences between a 4 into 2 into 1 and a 4 into 1?