Steve,
It sounds like you are on the right track with the T5 gearing. With regard
to the intake manifold, although your guy at Edelbrock may be "very
knowledgeable", he certainly isn't infallible; the Tiger lo-rise and
Cobra/Shelby manifolds are definitely not the same. That error
notwithstanding, the Performer RPM is still a good choice. Did you discuss
the Torquer II? Because of the limited space under the hood, if you use the
Performer, might I suggest you have 1/2" milled off the carb flange and
better yet, tilt it forward a bit too to give you a skosh more room. You can
always add spacers later as needed. On the other hand, if you used the
Torquer II I think you would have more room to start with.
I know you are pretty well settled on keeping the 2.88's, but just let me
take this issue as an opportunity to toss in some relevant physics. You made
the following statement: "Even my current 260 has decent enough torque in
4th from 2,000 RPM so 5th at the same rpm with my new 289 and an extra 125
HP or so should be even better." There are two factors that negatively
affect your comparison. First, the amount of power required to produce a
given response (whether you call it "torque" or acceleration) is
proportional to the speed of the car. A similar effect is seen with wind
resistance, which goes as the square of the speed, but the power needed to
overcome it goes as the cube of the speed. This is an important point that
is seldom appreciated. The way it relates to your comparison is, you will
only get 0.73 or 73% as much kick (torque/acceleration) at 2000 rpm in 5th
gear with the T5 as you now get in fourth gear at the same rpm. This is not
an insignificant loss of throttle response. In addition to this loss, I
wouldn't count on having more power available at 2000 rpm with the new motor
than you have with the 260. In fact, you will be lucky if you have as much.
The cam and intake manifold changes you are making all come into play at
higher rpm and generally detract from performance in the 2000 rpm range. The
same goes for gas mileage too. Your motor's best gas mileage is more likely
to be in the 3000-4000 rpm range. You may have noticed from Tom Hall's
recent posting that he also kept the 2.88's with his 5-speed. However, he is
running a roller cam motor which has a much flatter power curve that a flat
tappet motor and is a lot happier turning 2000 rpm than your motor will be.
But, give the 2.88's a try and see what you think.
BTW Steve L., I never doubted for a minute that you still had your old slide
rule. ;-)
TTFN,
Bob
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