Almost 40 mpg in my 1966 Chevelle !!!

[67-ls1]

Today I did a mileage run in my 66 Chevelle and demolished my pre-project goal of 35 mpg.
I filled my tank at a gas station near my shop and drove to the marina where we keep our boat. I make this trip a lot from home.
My GPS speedo said I drive 74.54 miles round trip back to the same gas station. This is compared to a Google map that shows 37 miles each way so pretty darn close.
I refilled to the point of spillage when I got back and it took 1.891 gallons.
That’s 39.94 mpg!
Granted the drive was probably 90% highway at speeds between 65-70, but I’ll take it.


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Build thread, more pics: https://ecomodder.com/forum/showthre...lle-30678.html

[cRiPpLe_rOoStEr]

What engine, transmission and differential is your Chevelle fitted with?

[67-ls1]

I have a 2013 LFX V6 out of a Camaro. 3.6L (217 ci) direct injected with 4 variable overhead cams. It’s rated 325 HP and connected to a 6 speed double OD auto trans. Rear end is 3.07 ratio with 26.5” tall tires. RPM at 70 mph is just under 1700 rpm.
The car weighs 3260 lbs with the tank full. The only aero is a front air dam under the bumper.
My best around town/highway combo before was 32 mpg so this was a big leap.

[EfficiencyLover]

I was hoping you might see this exceed your expectations, but wasn't too certain! :-) Congratulations on the outcome. I hope you enjoy the car. With the transmission you're running, how does it do in terms of acceleration? (I'm not familiar with the torque and power curves of that powertrain.)

[cRiPpLe_rOoStEr]

Originally Posted by 67-ls1

I have a 2013 LFX V6 out of a Camaro. 3.6L (217 ci) direct injected with 4 variable overhead cams. It’s rated 325 HP and connected to a 6 speed double OD auto trans. Rear end is 3.07 ratio with 26.5” tall tires. RPM at 70 mph is just under 1700 rpm.

Makes me wonder to which extent the aluminium-block engine, also shorter than the old-school engines originally available when the Chevelle was new, might have affected the handling too. BTW was the transmission also sourced from the Camaro?

[67-ls1]

Originally Posted by EfficiencyLover

I was hoping you might see this exceed your expectations, but wasn't too certain! :-) Congratulations on the outcome. I hope you enjoy the car. With the transmission you're running, how does it do in terms of acceleration? (I'm not familiar with the torque and power curves of that powertrain.)

Torque must have been an option for this engine in 2013 and the original owner did not check the box. It drops a gear on the freeway if you try to accelerate at all.

[67-ls1]

Originally Posted by cRiPpLe_rOoStEr

Makes me wonder to which extent the aluminium-block engine, also shorter than the old-school engines originally available when the Chevelle was new, might have affected the handling too. BTW was the transmission also sourced from the Camaro?

The car is super light for a 66 Chevelle. The engine and trans are from the same car and are lighter and sit back as far as I could situate them.

During the same project I swapped out the entire suspension for Hotchkis with sway bars front and rear, 2” dropped springs all around and 2” dropped spindles in the front. I’m going to change out the rear springs for 3” dropped shortly.

It handles like a go cart. I also added 4 wheel disc brakes so it stops well too.

I believe I could have gotten to under 3000 lbs but I caved and added Dynamat throughout and a couple other things for comfort.

[cRiPpLe_rOoStEr]

Originally Posted by 67-ls1

sit back as far as I could situate them

That's good. On a sidenote, have you never lurked about trying a transaxle just like some previous generations of the Corvette resorted to?

[67-ls1]

Originally Posted by cRiPpLe_rOoStEr

That's good. On a sidenote, have you never lurked about trying a transaxle just like some previous generations of the Corvette resorted to?

The engine/transmission combo I used came together with the ECM that runs them. It’s very difficult to run this engine without the trans.

A transaxle would have helped with the weight distribution but I probably would have lost two gears, both being overdrives.
I didn’t even move the battery to the trunk because I didn’t want 5 lbs of 2/0 battery cable.

[cRiPpLe_rOoStEr]

Originally Posted by 67-ls1

A transaxle would have helped with the weight distribution but I probably would have lost two gears, both being overdrives.

It doesn't seem to have really been an issue. Just to remind, the Corvette C6 and C7 had a transaxle based on the same 6L80 fitted to the 5th-gen Camaro when equipped with a V8. I'm just not so sure about the possibility to fit 6L50 internals on the casing of a Corvette-spec 6L80.