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Discussion Starter #1
So I'm currently restoring my 66 lemans (gto clone) convertible 4 speed. I love the car, I love working on the engines, and that throttle rumble from an american muscle V-8......................But we are now in 2012. Era of $4.50 a gallon gas prices and only going up from there. So now I'm looking at the engine trying to decide what to do. It is a tired old 400 2 bbl that will need a serious tune up and possibly rebuild. It's hard for me to justify putting money into an engine that will likely return single digit fuel economy numbers. I don't plan to drive it to work everyday but I would like to drive it at least a few thousand miles a year. Even a 10 mpg car vs 30 mpg a few thousand miles a year spells $1000 a year fuel savings or $10,000 over 10 years That's a lot of money!

So what are you GTO fans doing to fight the fuel prices? Any creative engine swaps I haven't thought of yet? LS1 is probably the most popular. What about the mustang 3.5 liter, rated at 31 mpg? Even those new turbo charged ecoboost 2.0 is getting crazy good MPG and has about the same power as the 400 thats in the car right now. But a GTO that sounds like a rice burner just wouldn't sound right. Anybody have that magic government conspriacy carb that gets 100 mpg that I've been hearing about since I was 10 (that's a joke)?
 

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Sell the GTO and buy a Ford Fiesta. :) In all seriousness, it your sole purpose was gaining better mileage, you would need to put on many thousands of miles to see an ROI. Now if your purpose is to take on the challenge, and have something cool to show off, well then hey, do it! When I need to save gas, I jump in my 2007 Pontiac GP and enjoy a ride that is much better than my 66, much quieter, much more comfortable seats, about as fast, but not nearly as fun!

I have a complete 5.7ltr from a 96 Impala SS with 3,000 miles sitting in my garage since 1998, but it will not be getting anywhere close to the 66!
 

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What am I'm doing to fight fuel prices? Nothing. It is what it is. When the 455 says it needs gas, it gets gas. For us northern boys, these cars are used only for a handful of months a year, if we're lucky. It's my toy. I don't look at gas prices. I drive it, enjoy it and make sure there's always money for the tank.
Drop an LS1 in it. But what will that cost you to convert? Price of the motor etc? Probably could put alot of gas in that 400 before you break even. And a Mustang 3.5? Sell the car before you do that.......

Not trying to sound harsh in my response, but, if you're that worried about gas, this hobby is probably not for you......Just one man's opinion.....
 

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Discussion Starter #4
I love everything about the car and have loved GTO's since I was about 5 years old. I love working on it. But I also have very hard time turning a blind eye when it comes to filling the tank. I can't help but do the math. 10 mpg vs a 25 mpg LS1 the driving only 3000 miles a year is a $1000 difference! That's a lot of money. Considering the 400 needs a rebuild it wouldn't take too long to pay for the ls1 swap.

I also bought the car because I wanted to drive it. I don't plan to trailer it to a car show or even enter it in a car show for that matter. Showing it off just doesn't do much for me. 't me it's all about driving it and it's hard to practically drive a 10 mpg car anymore. I guess the problem really has no solution.
 

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if you do much driving on a freeway or similar, you might want to switch to an overdrive transmission.
But 10 miles to the gallon with a 2barrel? Methinks there is something else wrong. Are you driving for economy or spinning the tires all the time? :)
What rear end gear ratio are you running?
Russ
 

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Gas mileage is about a whole lot more than just the engine. If you think that the engine out of a light Mustang that gives high mpg is going to produce the same results in a 4000 lb Pontiac, you're in for a very unpleasant surprise.

You say you want to drive the car --- ok, WHY do you want to drive the car? What enjoyment do you get out of driving it? If the reasons have anything at all to do with the car's "personality", then you probably wouldn't be happy with it after a swap anyway.

Also, don't totally discount the potential results of a fresh engine and appropriate gears. My own 69 GTO has a fresh engine and it's about as far away from a "mileage" engine as you can get. It makes 500 HP and is in a 4000 pound car that has 3.50 rear gears and no overdrive. On the highway it gets 11 mpg. I realize that's nothing to alert the media about, but considering what the car is and how it's built, that's pretty doggone good.

I'll bet you a buck against the hole of a rolling donut that your car with a fresh rebuild and "highway gearing" would deliver a lot closer to 20 than it would 10. No, that's not 30, but if you think you're going to get 30 mpg out of a 4000 lb. car by swapping in any engine that makes enough torque to actually move the car --- well like I said, you're in for a surprise.

Bear
 

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Okay, here's my reality: the most modern cars I have are two GTO's....a '65 hardtop with a 4 speed, 389, tripower, and 3.36 gears. I've had it 30 years. It gets about 12-14 mpg. I don't drive it a lot, but it sure is fun. My '67 GTO convertible I've also had for about 30 years, and it has the original 4bbl 400. It is an automatic trans. It came with a 3.36 rear gear, too. It would typically get about 15 mpg. Not a real pig. About 3 years ago, I swapped in a 2.56 rear axle assembly from a '69....and now get a bit over 20mpg on long trips and on the freeway. At 75-80mph. Excellent fuel economy. The 400 easily burns rubber and pulls like a train, yet with the lazy gear, it just loafs along on the open road. I've driven this car all over the US, and it is my regular driver. I have two "modern" trucks, both Toyota's, but the newest CAR I've ever owned is my '67 GTO. Maintained and taken care of, these old Pontiacs can be fuel efficient and fun to drive at the same time. If you're really concerned about fuel economy, check into an overdrive transmission, auto or standard. There are guys on the other forum (pyforumsonline) who also get over 20mpg running real Pontiac engines with the proper gears and or an overdrive. These were well designed engines, and with a little care, work Just Fine. I've had a bunch of GTO's over the years, and NONE of them got single digit fuel economy. Expect 10-12 mpg for a high HP, steep geared monster like Bear's, and high teens to low 20's for a mild combination like mine.
 

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Another thing: with your tired old 2bbl 400, a simple engine rebuild with a decent cam, 87cc heads (or custom pistons) and a Quadrajet carb, combined with 3.08 gears to work with your 4 speed, you should get about 17-19 mpg going down the road. The Q-jet is more miserly on fuel than the 2bbl due to its design, but will give you all the power you need when you decide to waste some fuel!!
 

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Okay, here's my reality: the most modern cars I have are two GTO's....a '65 hardtop with a 4 speed, 389, tripower, and 3.36 gears. I've had it 30 years. It gets about 12-14 mpg. I don't drive it a lot, but it sure is fun. My '67 GTO convertible I've also had for about 30 years, and it has the original 4bbl 400. It is an automatic trans. It came with a 3.36 rear gear, too. It would typically get about 15 mpg. Not a real pig. About 3 years ago, I swapped in a 2.56 rear axle assembly from a '69....and now get a bit over 20mpg on long trips and on the freeway. At 75-80mph. Excellent fuel economy. The 400 easily burns rubber and pulls like a train, yet with the lazy gear, it just loafs along on the open road. I've driven this car all over the US, and it is my regular driver. I have two "modern" trucks, both Toyota's, but the newest CAR I've ever owned is my '67 GTO. Maintained and taken care of, these old Pontiacs can be fuel efficient and fun to drive at the same time. If you're really concerned about fuel economy, check into an overdrive transmission, auto or standard. There are guys on the other forum (pyforumsonline) who also get over 20mpg running real Pontiac engines with the proper gears and or an overdrive. These were well designed engines, and with a little care, work Just Fine. I've had a bunch of GTO's over the years, and NONE of them got single digit fuel economy. Expect 10-12 mpg for a high HP, steep geared monster like Bear's, and high teens to low 20's for a mild combination like mine.
:agree with the 2:56 gear and the 463 i was getting close to 20 HWY, have a 3:55 12 bolt sitting in the shop and it will probably not get installed until gas comes down, no need, i don't race and the motor and rear combo will still obliterate the tires from anything up to a 20mph roll, show me a fiesta that will do that.

I also agree with 68GreenGoat the price of gas is the cost of entertainment especially for us non-sunbelt states, night at the movies costs me 60 bucks these days, thats a 110 mile round trip in the Tempest. I can wait to see the movie on net flix, but i can't wait to drive my car when it's nice out!!
 

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I know you said you can't help but feel bad because of the poor fuel economy, but think about it. Did you buy the car to think about all the gas station trips, or for enjoyment of a REAL car with a sound and a V8 that you just don't see anymore? :cool

These cars are a time warp, a tribute to a time where life was simpler (so is legend, I can't even legally order a beer yet LOL) and to pure automotive bliss. Roar or cruise down the road, you cannot beat these cars for that special feeling. Mileage should not be a dealbreaker, and as already said, get some 2.73 gears and a Q-jet carb and maybe even an OD tranny if you really lose sleep at night.

I've heard of people putting LS1s in old schools, but my best guess is you would need to beef up the stock internals, as they put down good horsepower numbers but torque is what you really need to move a car this big and heavy.

My dad said something to me yesterday that really changed my outlook on life. I asked if they made garage door windows that had UV protection (to protect a certain Pontiac) and he said of course, it's more expensive but it's just money.

You save $$ in some places and spend your hard earned money on the things you really enjoy in life. I'm the cheapest guy you've never met, but where is the joy in never enjoying the fruits of your labor?
 

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:agree

Good advice guys. If mileage for the least amount of investment is the goal, I like the idea of the fresh rebuild and road gears like 3.08 or less. But... If you are not as worried about a quick return on investment, a more costly (most likely anyway) route like a LT1 swap would not be all bad.
 

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Discussion Starter #12
Thanks for all the feedback. I'm glad to hear all that. I've done about a day of researching swaps and concluded the LS1 isn't all that it's cracked up to be. I thought it was some miracle space age engine that got 28 mpg in a corvette. Reality is it's just a truck engine v8 in a very aerodynamic car that can go down the road with very low RPMs from the tall gears. Most experts are swapping in a 5.3 out of silverado because it is much cheaper and basically the same engine. After reading all the replys on here I'm thinking I will be happy with high teens for mpg in my stock 400. 10 mpg was just going to be a little much. To be honest I haven't even driven the car more than 100 ft. I bought it 2 years ago, it sounded good but the tires were too bad to take on the open road. I'm restoring it now and hope to be done by August.

BTW Does anybody know off hand what a 66 lemans convertible 4 speed with a stock 326 (the 400 is out of an 68 catilina) had for a rear end ratio? Also I wasn't sure I follow the post about the quadra jet? Are you saying a 4 bbl quadrajet would get better mileage than the 2bbl provided I kept my foot out of it? What model quadrajet? Is this the preferred carb for the car? Is that with a cam change or the stock 2bbl cam?
 

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KingJacobo, you are wise beyond your years...very well stated, indeed. Eou, your '66 most likely came with a 3.23 rear gear....std. for a stick LeMans in that year. Pretty much a perfect ratio. A 3.08 would be better for fuel mileage, and the gears would work in that carrier assembly. A jet will get better mileage than the 2bbl, as I stated, due to primary design. Pretty much any '67-79 unit will do....earlier, and Pontiac, is best. A 2bbl cam is designed for low rpm power, and would be fine with lower compression heads or dished pistons...with stock high commpression heads, a cam with more duration and overlap, like an 068 grind, would be better. LS1 engines have LESS torque than a stock Pontiac 389....and about the same HP. Not the magic bullet at all. Good mantainence, gearing, and driving habits are. I've been in the automotive business for over 30 years, and have driven pretty much everything out there. I've also worked on a bunch of the stuff "out there". I've driven 100's of thousands of miles in GTO's....as my only mode of transportation. Believe it or not, their full frame construction, rear wheel drive, and good build quality put them ahead of most modern cars in every area, including driver comfort, except wind noise. They are great cars for everyday use, even now, 45 years later.
 

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Discussion Starter #14
I wasn't really planning on changing the cam. The engine actually did run good when it run. I might not even rebuild it. So if I don't do a cam change would you advise a 4bbl cam then?
 

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?????? I t hink you're getting ahead of yourself a bit, all due respect. I suggest you give it a tune up and drive it around for a while. More than 200 feet. You'll figure out what you want and need as you get familiar with the vehicle and the way it operates. Have fun!
 

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Discussion Starter #16
In theory I 100% agree with that. But I'd like to take care of any issues now and set it the way I want it while the car is all stripped down, hasn't got paint, fenders are off wiring is removed and it's easy access to everything. I'll take compression to see if I go to rebuild it. As far as the carb, the intake manifold is a little worse for the wear and at the very very least I'd want to regasket that as well as rebuild the carb. If I do that, I might want to upgrade to a 4bbl manifold and carb. The carb also doesn't have an air cleaner (previous owner says it hasn't run more than 10 mins of it's life without one but it does make me suspicious). So before I buy a two barrel air cleaner, and regasket the intake I'd like to figure out if I'm going to change the carb too. But if I definitely need to change the cam to get the 4 bbl to run right I probably will just stick with the 2 bbl for now..............Basically I'm just considering all my options before I tear into it too much. Right now I'm just waiting on everything till I take a trip to my GTO parts guy in central oregon this weekend. I've heard "the goat herder" is famous for GTO parts.
 

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The cam doesn't know what kind of carburetor is feeding it.. :D

The difference in cams mostly has to do with the rpm range where they cause the engine to be at its peak volumetric efficiency. A "low performance 2bbl" cam is going to be optimized for lower rpm range operation. That's going to give you a smooth idle and good torque production on the street at lower rpm, at the expense of not maximizing higher rpm power and torque.

Bear
 

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Discussion Starter #18 (Edited)
Copy that. Thanks for the advice and help. I'm starting to get this whole gas engine thing slowly but surely. This is the first vehicle I've ever owned with spark plugs instead of glow plugs. Believe me the thought of a cummins GTO crossed my mind. But when I mentioned it to my friend, he beat me.......I probably deserved it.
 

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I was going to say what Bear said, but he beat me to it. One of the hardest running GTO's I've ever had was a '66 4 speed car that had a $150 junkyard engine out of a '67 Bonneville....it was a 2bbl 400 V8. I bolted a tripower intake and carbs onto it and won a ton of races. With a 2bbl cam. Lots of low end and mid range power, usable power, there.....Just change the intake to a Q-jet and a Tripower and go from there, IMO. Leave the rest alone.....for now!
 

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I was going to say what Bear said, but he beat me to it. One of the hardest running GTO's I've ever had was a '66 4 speed car that had a $150 junkyard engine out of a '67 Bonneville....it was a 2bbl 400 V8. I bolted a tripower intake and carbs onto it and won a ton of races. With a 2bbl cam. Lots of low end and mid range power, usable power, there.....Just change the intake to a Q-jet and a Tripower and go from there, IMO. Leave the rest alone.....for now!
Always wonder about these threads. A lot of you gave him great information some he might not want to hear and he disappears? I think the red flag was his first post saying he had ram air 3 iron heads and is running pump gas on a 10.5 or more to one motor. I know it's been done but really difficult unless you are one hell of a tuner . Maybe he will come back . Doug
 
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