----- Original Message -----
From: "Doug" <dougfr@comcast.net>
To: <triumphs@autox.team.net>
Sent: Tuesday, December 05, 2006 12:17 AM
Subject: [TR] TR6 Exhaust Manifold
> Old subject but need a little advise. I'm upgrading my '69 TR6 engine
> with a
> better street cam and porting, etc. Stock carbs for now. The original
> factory exhaust manifold is cast iron with a single exhaust pipe system.
>
> Would it give me improved breathing if I went to the 73-76 cast iron
> exhaust
> manifold with the dual exhaust pipe system or should I remain with the
> single?
Doug -
I would reference Kas Kastner's Competition Prep manual on this. Kas
found that a single exhaust for TR6/GT6 engines made more power and torque
except at the top end of RPM's. He found that 2 1/2" diameter exhaust pipe
gave the best performance. There are differences between the early and late
heads to consider (so I'm told). A late exhaust manifold will not fit an
early style head. It would depend on which set up you are using.
Given what I've read from Kastner's testing, you'd be better off to
retain the original exhaust manifold and go to a bigger diameter single
exhaust for performance gains over the stock setup.
Tim Hutchisen
71 TR6 (S2 cam; ported; bored; balanced; lightened flywheel; stock exhaust)
70 GT6+ (stock for now.............)
74 Spitfire (in pieces)
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