Chris,
A pearl of wisdom contributed a couple of years back by Steve Laifman which
he credits to his father might be appropriate here: something to the effect
that "Show me a man who knows his gas mileage and I'll show you a loser."
That wisdom is probably particularly apropos wrt Tigers. However, even
Steve's dad might be concerned about only 3.3 mpg. As a personal anecdote,
many years ago when I was running the equivalent of the Ford Motorsport
A-303 hydraulic cam in a 289 with 289 heads and about 12:1 compression
ratio, I would regularly get 25+ mpg on the highway cruising at 70-80 mph
(with 2.88 gears). I don't do nearly that well now which may be the result
of several factors: bigger cam, ported 351W heads, unleaded oxygenated gas,
etc. Through almost all of this time though, I have used the same basic 600
cfm vacuum secondary carburetor, so it is at least capable of delivering
very good mileage if properly jetted (including power valve). As long as
you stay out of the secondaries, I see no reason why a 600 cfm
double-pumper should do any worse. I don't recall if you told us what jets
you are using, but a good starting point would be 65s in the primary and
maybe 68s or 70s in the secondary. I would also start with the stock 6.5
power valve or thereabouts. You can go to the Holley Web site and get
instructions on how to tune your carb, so I won't bother you with my two
cents worth. The jetting for maximum power is about 10-15% richer than for
maximum mileage, so you will have to compromise a bit in this regard. But
with any kind of decent tuning, and keeping the giggle factor to a
reasonable level, you should get at least 10 mpg around the island and at
least 15 mpg on your trip to Texas with the 600 cfm double pumper. It's
entirely possible that you could even do a lot better, depending on the
details of you engine, but I would be surprised if you could do
significantly better with any other carb.
Brgds,
Bob
At 09:01 PM 5/29/00 -0700, Chris Vaught wrote:
>well today i took the tiger, girlfriend and her daughter to wakiki beach. it
>is about a 22 mile round trip or so. i do not have a fuel gauge so i decided
>to fill up before i left for the beach and before i made the trip home. i
>used 3.3 gallons on a 11 mile trip! i did romp on it a couple times just for
>fun. anyway that is alot of gas to be drinking when i plan to drive from
>L.A. to Texas. i have a holley off of a 84 mustang, a 600 vacum secondary,
>and a 450 cfm vacum secondary. which one would offer the best performance
>and MILEAGE after i rebuilt it? i would hate to see my gas bill across the
>U.S. in august at 4 mpg.
>thanks
>chris in hawaii
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