Author Topic: MPG new best  (Read 2116 times)

Offline 68 Firebird

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MPG new best
« on: July 18, 2016, 02:55:12 PM »
Took the Firebird Sunday to visit an old friend and clocked the mileage.
Filled up in the am and drove 153 miles, that were 80% highway at 65 miles an hour.
On the way home I stopped at same station and topped off and only used 9 gallons to refill.
We had to push in the last half gallon, but that still means she averaged 17 miles per gallon!!!
The car is a 68 Firebird with 3:08 gears and th400 with 13"Continental Conv.
With the Wife and kids in the car there was no heavy throttle, just cruising.

Heck the Firebird gets better mileage then my wife's Trailblazer!!

Gerry

Offline Frank400

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Re: MPG new best
« Reply #1 on: July 18, 2016, 07:00:09 PM »
Hey Gerry,

  what's the engine in that 'Bird and what is the carb number ?

Offline 77cruiser

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Re: MPG new best
« Reply #2 on: July 18, 2016, 07:42:35 PM »
That's pretty good.  As long as we're on the topic. Mine is a 421 sbc dynoed 530 hp 540 tq. did a 350 mile round trip drive & got a touch over 18. Car is a 77 Monte it has a 3.73 rear 200/4r with a lockup converter.
Let the stories begin. ;D
Jim

Offline 68 Firebird

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Re: MPG new best
« Reply #3 on: July 19, 2016, 06:19:53 PM »
Original drivtrain ,motor 68 400 with 068 cam, trw forged pistons, factory iron intake, 7043266 Q-Jet setup by Cliff a few years back. And ram air pans and AC style pulleys with aluminum radiator.
DUI HEI setup 12 initial and 32 total with another 14 from ported vacuum.
TH400 with 13"Continental Conv and mild shift kit, factory 3:08 geeks and auburn posi.

Gerry

Offline Cliff Ruggles

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Re: MPG new best
« Reply #4 on: July 20, 2016, 04:12:41 AM »
Good numbers not having an OD transmission.

The best fuel mileage I've achieved here was with a 1967 Impala SS.  I bought and restored the car about 20 years ago, and replaced the PG trans with a 4L60 and custom build non-LU converter.  The 327 was completely rebuilt with a stock 350/300hp camshaft, and it had 3.31 gears out back.  It averaged 18mpg's for "normal" driving and would do mid 20's on trips running around 70mph.

Maybe we should start a thread on the MPG results some folks are getting from their older vehicles.....Cliff

Offline Frank400

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Re: MPG new best
« Reply #5 on: July 20, 2016, 09:36:31 AM »
1968 Camaro 327/210, 100% stock (motor never apart), 1968 iron Qjet intake and 1 5/8 headers, 5 speed  NON overdrive (Richmond 5 speed) and 2.73 rear. 

   Carb is a 1980 17080207 (dual .120" main air bleed carb, now .070 both main air bleeds), with Cliff's parts and everything that I've learned from his book and this forum.  Home built factory point type distributor converted with HEI internals and custom curve, vacuum advance as well (very important !)

   I get 25 mpg all day long on the highway and I LOVE QJETS !

Offline 77cruiser

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Re: MPG new best
« Reply #6 on: July 20, 2016, 10:58:00 AM »
That's excellent Frank.
Thing about my car it came with a 305 2 barrel. Swapped to a Qjet dual ex. headers Holley 28 Z intake.
Then I had a 383 about 425 HP Qjet with adapter on a RPM intake.
Now the 421 Vic Jr. with an adapter.
Mileage in all cases were 18-19.
Jim