On Sun, 5 Jan 2003, Timothy Holbrook wrote:
> Two quick questions about this:
>
> 1) Which head is "better" (ie: breathes better), the early or the late?
> As I understand it, the early and late head share the same exhaust
> ports, but the intakes changed. The early head (which I have on my 71)
> has different intake port spacing than the late head (which is the head
> that was used on all years for PI cars). Just wondering which head is
> preferable...
Late heads a lots better (in an unmolested from the factory state). You
can make an early head flow well, but it takes alot of black magic.
FWIW, the difference as far as a street car is concerned is negligible.
The benefit shows up when you try to get those last few HP (and that costs
the most to do).
So, for most people reading this list, early/late is not likely and issue.
> 2) I have also heard that the later style intake manifold is better,
> due to longer and straighter runners. I understand that a straighter
> runner is preferable, but why is longer better? I have heard that a
> longer runner produces more low-RPM power, a short runner provides more
> high-RPM power. Is this correct, or have I got it backwards?
Long intake runners allow the motor to make more torque. That's why racer
run those trumpet thingies.
You have it just about right.
> Thanks!
>
> Tim Holbrook
> 1971 TR6
C ya,
rml
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